I have an old Savage model 24 over/under. Gun is marked 24 Series P on the 20ga. shotgun barrel. The upper barrel is 22 Win Mag R.F. Serial number prefix (C) puts manufacture in the late 70's. It is my understanding that all of the Series P guns were .22LR over 20ga. There is no evidence that the barrel isn't original, no evidence of aftermarket welds or rebluing. Anybody have some insight into these guns?