A friend sent me this picture which is not of the best quality; he asked me if I could identify or know anything about a (VERY FAINT) mark in front of the "dot" on the caliber marking on his OM .41 Mag.... He says it is an "F", and, he insists is stamped (I disagree, but have never seen the actual marking on the gun). I told him that I would ask the members here but, in my opinion it is nothing more than some previous owner's personal marking. If anyone can shed any light on this marking, we'd sure appreciate it. THANKS, John