Kutter,
In my "accumulation",I have an example of very early post WW2 German commercial hunting ammo, that was made from military brass. The military headstamp numbers were removed(trepanning)and new numbers stamped in their place.This resulted in numbers in a groove, but didn't seem to have bad effects. I don't know if a single stamp was used, but I guess it was, since this was a factory operation.The numbers seemed to have been lightly stamped, perhaps out of concern for displacing metal.Mike