In the late 1930's, the model 100 reached a turning point.

Supply shortages and rationing caused by the war effort became increasingly severe, and the use of gold was restricted.　Günter Wagner chose (or was forced) to make constructional and material changes.

In February 1938, the use of gold nibs for the domestic market was forbidden by the government. Following it, as of May 16, 1938, pens were fitted with palladium nibs⁽¹⁾⁽²⁾(Pelikan Schreibgeräte) (as from November 11, 1939, Pelikan fountain pens were fitted with CN nib).

The model 101 was also discontinued in 1938.

The precious metal models or “luxury models” of the model 100 (model 110-112) were still on the 100th anniversary catalog (1938) for the domestic marke⁽³⁾t, but no longer on the corresponding export catalog. In 1938, they were completely discontinued, and replaced with the precious metal models of 100N released in the same year. By the end of March 1939, all precious metal models for the domestic market were discontinued (Pelikan Schreibgeräte). From then on, the precious metal models of 100N were exclusively destined for the export market as found in "Pelican” catalog (1939)⁽⁴⁾. At the time, the export trade was forced by the government to secure hard currency (Pelikan History).

As of October 11, 1939, pens were fitted with chromium/nickel (CN) - steel nib (CN nib), as the use of palladium nibs for the domestic market was forbidden by the government (Pelikan Schreibgeräte).

Getting back to the model 100, the most notable feature of this generation (the sixth generation) is that for the first time in the model 100, the nib was made of palladium. While the IBIS, the economy model, already featured a palladium nib, finally, the higher-end 100 model was forced to adopt it as well. Perhaps in an effort to at least make the nib look as good as a gold nib, the Pd nib is gold-plated (Fig.3). Different from gold nib, there is no markings that indicates the purity of palladium⁽²⁾⁽³⁾. There is no nib specification on nib (nor the cone, but feed?)(Fig.2-2).

Major changes were also made in the material of the body and the cap. Ebonite had been the basic material of fountain pens. But, it was unstable and susceptible to water and UV rays. Beginning with Sheaffer in 1926, celluloid came to dominate the manufacture of pens until after World War II. From the start, Günter Wagner used celluloid for sleeves, later for bodies. The company, however, stayed with ebonite for cap tubes and cap tops until 1938. Then, they (Günter Wagner) gradually moved toward celluloid, first for cap tubes, then for cap tops, and finally for filler mechanisms⁽⁵⁾. They stayed with ebonite for the filler mechanism somewhat longer, as celluloid proved difficult to mill in the distinctive manner of the turning knob. But they did produce a milled celluloid knob for a few years before the introduction of the smooth knob (Pelikan History​). By 1939, except for foreign production (e.g. Milan), ebonite was gone from Pelikan pens (Pelikan History). If well kept/cared for, it is not so easy to distinguish between celluloid and ebonite at a glance. A hint of the smell of camphor indicates that it is made of celluloid. As for the cap of this fountain pen, only the cap tube is made of celluloid, suggesting that it dates from the transition period from ebonite to celluloid (or cellulose acetate). Other differences is the sealing and ventilating system of the cap. With the both cap top edge and the top edge of the grip section being flat (Fig.3-2 right, Fig.4 right), they form a frontal plane seal⁽⁶⁾ as in the 1st generation. It is likely that the material of the section was changed from ebonite to cellulose acetate. As shown in Fig.5, 6, 7, the filling system is further changed. Instead of the notch, the ridge along the inside of the piston guide (Fig.6-2) prevents more firmly the rotation movement of the piston rod, converting the rotational motion of the spindle into the up-and-down motion of the piston rod. There is no guiding pin hole, no arrow on the turning knob (Fig.5 right). The material of the filling system had been changed from ebonite to celluloid. 

Lastly, there was another major change in the piston seal. My Pelikan 100 (ca.1938) came with a black elastomer seal (early type)(Fig.8 right). The new celluloid piston rod is not compatible with the previous ebonite piston guide or spindle. It is also impossible to fit a cork seal to this celluloid piston rod. Therefore, it can be inferred that the black elastomer seal and piston rod on this model 100 are both original. Taken together, it appears that the black elastomer seals were introduced to the model 100 at the latest in 1939, and (gradually?) replaced cork seals. As for the 100N, the cork seals were used still in 1940 (@stoen). So, the transition period may have been longer (see Pelikan 100N (ca.1942)).
 
Note;⁽¹⁾Putting it the other way around, gold nibs were still available, for the export market. “The question of gold nibs is pretty obscure”. “...logically gold nibs were permitted for export until "about" 1940...After 1939 gold nibs got very scarce for any market... After April 1940 the Germans knew that they would have to fight French, then the British and probably the Russians…”(Rick Propas). Interestingly, Fig.9 is the export version of the model 100. "Export" imprint is seen on the sleeve near the cone. Please also refer to his timeline. "In Switzerland, model 100 with gold nibs was available during the whole wartime. Günter Wagner had its own repair center and ink manufacture in Zurich which was able to deliver pens and gold nibs (from stock) during the entire war time. Some of them were even marked with "Export"(Christof Zollinger). It seems that the situation varied from country to country, region to region.
⁽²⁾"Palladium, although considered precious metal from the platinum group, was not as expensive as platinum, and had been used in the automotive industry in the 1930’s” (@stoen). Montblanc and Soennecken also used Pd nibs for their wartime flagship models (Fig.10). According to PenCluster, Pd nib was palladium/silver alloy, but the purity of palladium is not mentioned. It is interesting that three nibs were all German manufacture made.
⁽³⁾When the catalog was issued, gold nibs had already been forbidden. But, the wide variety of nibs on the catalog suggests that pens were fitted with gold nibs (installed from stock?), as it is unlikely that Pd/CN nibs had that wide varieties. “After then, they were fitted with Pd and then CN nibs, but it is almost impossible to know because some existing gold nibs were scrapped during the war. I suspect that many people had their CN nibs replaced with gold nibs after 1948, especially if you were wealthy enough to have a 100N…” (Rick Propas). I happened to find one example of the precious metal model with Pd nib.
⁽⁴⁾The wide variety of nibs on the catalog again suggests that pens for the export market were fitted with gold nibs.
⁽⁵⁾As a result of that, “...today many of the pens come down to us with mixed materials (e.g., cap tube of celluloid with cap top of ebonite). Some of these pens may be later “marriages” but many are quite correct...” (Pelikan History).
⁽⁶⁾I’m not sure if these changes were made to reduce the manufacturing processes/cost. It seems that the company thought that practically the frontal seal was tight enough.
*As far as I know,  “Pelikan GÜNTER WAGNER” engraving also appeared on the cap top in this generation.