Boatbum:

Sometime in the 1990s, Griffin & Howe had a number of guns for sale that came out of the DDR after the fall of the Berlin Wall. All had been hidden by their owners during the era of Soviet control of East Germany and they all had similar pitting issues to those shown on your gun. If Paul Chapman is still with them, he could tell you more about that group of guns and what restoration techniques were used to rectify the issues with them.