Don't let the wives see that remark about "woman". We'll be crucified...they did the vast amount of the work on these and other guns. I think their machine skills probably were among the best and could compete with anything you would see today. The marks are simple machine process and mean nothing. My LL low number M1Rifle has little file marks at some receiver corners that break the edges and I wouldn't change that for anything. If you look at any original finish military weapon, you would probably find these machine marks. No concern...