Welcome to the forum! If it has a 1920, then it is probably not a alphabet luger, as it is either a ww1 with the date taken off, or a commerical that came into military service...
Does it have a stock lug?
And all things considered, a shooter 9mm is worth more than a shooter 7.65mm (also known as 30 luger). The 7.62 x39 is a rifle cartridge used by nato
Ed