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

The precious metal models or “luxury models” (model 110-112) were still on the 100th anniversary catalog (1938)⁽³⁾, but no longer on the corresponding export catalog. They were replaced with the precious metal models of 100N in 1938. 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 were only 100N variants and they 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). Model 101 was also discontinued in 1938.

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).

As seen in Fig.3, Pd nibs were gold-plated (gold plate at the tip is gone). Different from gold nib, there is no markings that indicates the purity of palladium⁽²⁾. There is no nib specification on nib (nor the cone nor the feed)⁽²⁾⁽³⁾. As for the feed, in 1937, the feed without recess (slot) was introduced (Fig.11 right) (Pelikan-Guide).

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 gradually moved toward celluloid, first for cap tubes, then for cap tops, and finally for filler mechanisms⁽⁵⁾. The company stayed with ebonite for the filler mechanism somewhat longer, as celluloid proved difficult to mill in the distinctive manner of the turning knob. But the company did produce a milled celluloid knob for a few years before the introduction of the smooth knob. By 1939, except for foreign production (e.g. Milan), ebonite was gone from Pelikan pens (Pelikan History).

Fig.5 shows the cap top and cap tube. 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. The logo on the lateral side of the cap top (Pelikan GÜNTER WAGNER) differs from the previous one (Fig.5 left)⁽⁶⁾. Other major differences are the sealing and ventilating system of the cap. With both cap top edge and the top edge of the grip section being flat (Fig.12 bottom), they form a frontal plane seal⁽⁷⁾ as in the 1st generation. There still exists a groove inside of the cap tube but some pens including my pen don't have vent holes⁽⁷⁾. As shown in Fig.6,7-1,8, the filling system is further changed⁽⁷⁾. Instead of a tiny pin or a notch, the ridge along the inside of the piston guide prevents the rotation movement of the piston rod (Fig.7-1), The ridge guides the piston rod more firmly. There is no guiding pin hole, no arrow on the turning knob (Fig.8).
 
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 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 110N…” (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). So, other pens in this generation may have parts made of ebonite.
⁽⁶⁾As far as I know, this logo appeared in this generation.
⁽⁷⁾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, and that without vent holes, the groove alone was capable of both equalizing the cap pressure and ventilating the grip section.
⁽⁸⁾Fig.12 shows two pens in the 6th generation. Both pens have the feed without recess, but the top pen has a diagonal seal, suggesting that it is the transitional model.
*I have two model 100s with Pd nib. One has a cork seal, and another has a black elastomer seal (early type) (please see Pelikan 100 (ca.1940) Fig.5).  If all parts of my pen are original, black elastomer seal might have been introduced as early as 1939.