I am not that purist. I don't go in for Nazi emblems or literature, but guns are amoral; they are "things" and do not, cannot, have any sense of right or wrong.
But refusing to own a "Nazi" gun presents some problems. Any gun made in Europe prior to 1945 could have had a Nazi owner. Those drillings and shotguns taken from German homes by American soldiers were most likely owned by Nazis or Germans who supported the party. And they might not be German guns; in times of peace, German sportsmen bought guns made in England, Spain, the U.S., and other countries. They might not have any swastika mark, but the owner might have been "sieg heiling" at the top of his lungs.
Besides German guns, the German army and Nazi party organizations used captured weapons, even giving an official German designation to the M1911A1 pistol, and making .303 ammunition for captured SMLE's. Such guns were "repatriated" after the war, so that Colt .45 could have been in Nazi hands.
It is very likely that .32 caliber pocket pistols made in Germany in the war years were used by some arm of the German government or the Nazi party. And even gun clubs were controlled by the "Kraft durch Freude" organization and limited to members of the Nazi party, so a "bringback" Walther Olympic had probably been in Nazi hands.
As for Imperial or Weimar era Lugers, they didn't vanish in 1933. They were issued to Nazi party groups, like the SS, as well as to police and, of course, the Wehrmacht. It is pretty safe to assume that any Luger in Germany during the Nazi era was used by the German military, police or Nazi party organizations, no matter what the markings on it or when it was made.
Whether to eschew "Nazi" guns is a personal choice, but I don't see how anyone could collect any representative historical selection of guns from before 1945 and not have any gun that might have been used by a Nazi.
Jim