New to forum.Hi!I prowl old country stores and pawnshops in my travels looking at old shotguns.Have picked several treasures.Saw a 12ga pump in N.C. that has since intrigued me.On top was "Winchester/------"Can't remember the other name other than it was a well known mfg'er.The odd thing that got to me was on top of reciever was a 1/2" hole.I slid the action forward and a lug popped up into the hole,presumable to help lock the action.Gun was serviceable(owner claimed it shot),but in bad appearance,bbl's zero blueing,stock dirty.I.E. good project gun.My ? anyone know anything about it?Sorry for lack of details,but wife was in truck waiting.I plan on going back next trip to cabin in N.C.ps-hole was square.