As stated above, the cap top, cap tube, sleeve (and probably clip) are white gold filled. The ground metal seems to be nickel silver (also known as German silver or "Alpacca")⁽²⁾. The inside of the cap top ground metal is made of ebonite, as in the 100 series. The cap tube ground metal is also lined with ebonite tube to reinforce it. The model 110 had three patterns (diamond, barley, and wave) on the cap and sleeve (Pelikan-collectibles). My pen is decorated with plain stripes alternating with wavy patterns.

My pen has a tapered grip section characteristic of the fourth generation (ca.1933-), while it has 4 vent holes cap of the third generation (ca.1931-) (Fig.1). So, this pen seems to the transitional version from the third generation to the fourth generation, or Günter Wagner utilized the old part (cap tube) of the preceding generation.

The precious metal models or “luxury models” (model 110-112) were still on the 100th anniversary catalog (1938), but no longer on the corresponding export catalog (Pelikan Schreibgeräte​)⁽³⁾. By the end of March 1939, all precious metal models for the domestic market were discontinued (Pelikan Schreibgeräte). 

Model 110 was reissued as "Originals of their Time 1931 White gold" in 2000.

Note;⁽¹⁾White gold is an alloy of gold and at least one white metal (usually nickel, silver, or palladium).
⁽²⁾At that time, Pelikan used nickel silver for silver-colored clips. My model 110 has been used for many years, and the white gold coating has partially peeled off the clip, sleeve, and cap, revealing the ground metal. They all appear to be the same metal.
⁽³⁾The precious metal models or “luxury models” for the export market were replaced with those of 100N in 1938 (e.g. 101N White Gold).