Hi Mauro,

You are correct. Euro Mausers can easily be identified by their German proofmarks.

The 1973 change from date-digits to date letters was the result of the revised German proof laws.

Pre 1971 and post 1991 Postwar German fire proofs closely resemble the pre-1939 proof mark (with an added N for Nitro underneath). A slightly different proof mark can be found between 1971 and 1991, resembling a much more stylized eagle.