It's possible that you have a Brazilian Model 1935 with a replacement bolt or, since it would have been made when the Nazi party was in power, the Waffenamt stamp was applied to the bolt on all Oberndorf Mausers, even the export guns. The odd things is that you'd expect an export military Mauser to have the country crest stamped on the receiver ring rather than the Mauser banner. The proof marks on your rifle look exactly like a picture of Brazilian 1935 that I found on the internet.
