It is not clear who did the milling, but at least by my unscientific observation there are more ex-Bavarian revolvers in the market with the marking intact than with it milled out. I also know for a fact that Bavaria sold these centrally, so they were all treated alike, which means the milling occurred post-service by some subsequent wholesaler.

In view of the more restrictive gun laws in West Germany which limited the customer base, selling these cheaply to rod-and-gun clubs on US bases, most conveniently located in Southern Germany where these guns were on offer, was an attractive option.