See what looks like casting or sheared metal on the bolt handle retainer spring pin. I bought this gun used. This is the second time I took it apart to clean it. I don't remember this there the first time, but maybe I didn't pay as much attention. I went to a local shop and looked at a bolt of one they had ont he shelf, it looked like a normal pin to me. So is this something I should worry about? Is it just casting that didn't get trimmed?