Jani,
I had that feeling, at first, but wouldn't a 1920s rifle carry proof marks(I noted it still has Heym marked barrel)?
BTW, Rolf Heym had died by 1971 when I had my first experience with them, and they were controled by Mauser.At this time they were making the Mauser Mods.2000,3000,and 4000 in the Muennerstadt facility.By the time I returned in 1976, the Courts had returned ownership to Frau Heym (there were no childern).Herr Peter Bang was running it at the time.Later she remarried, to the brother of the Austrian gunmaker Desulnnige(spelling?).
Mike
