This is on the right side of a 9mm 1920 DWM pistol. This is the only stamp on the right side, the left side has a crown with an N under it. Any help would be great. The SN is 7991. All the parts are stamped with 91 even the small ones. This pistol was a gift from my uncle who told me he took it from a german at a supply depot in germany in 1945. I have had it for about 25 years my self and just took a new intrest in it. Thanks for the help.