The defacing is also inconsistent with what you see on most RC's. Saying something never happened on an RC is a fool's game, they're just too diverse, but by and large you'll see the swastica blasted off with a punch rather than the whole proof defaced.
What kind of mark? Most countries that fielded these after the war just used them as is. We're usually left grasping at the country that used it based on how they modified it for their own equipment (see: French alterations to fit their slings) or circumstantial evidence based on where it was imported from. Some are pretty well documented due to their specific overhaul process (Yugos, USSR), but those are the exceptions rather than the rule.
edit: There are a few examples where you have unique markings put on, but again, exception rather than the rule. The DDR VoPo sunburst is pretty discrete all things considered, and then you have the Israelis.