Thanks for all who offered opinions, suggestions, etc in attempting to identify the mark on my mag. I now have authenticated identification from a renowed collector of Lugers whos name I shall not reveal for obvious reasons. Aparrantly I am the proud owner of a "one of a kind" mag manufactured especially for Ronald McDonald. This mark was originally the McDonalds "arch over M" but some idiot buffed the arch off when they buffed the serial number off.