I just bought a used Rem. 1100 12 ga. from an individual at a gun show. When I took the gun apart to clean it thoroughly, I noticed that the "guide pin" inside the upper left part of the receiver that slides inside the slot on the barrel, was missing. When I reinstalled the barrel and tightened the forearm nut, everything was tight and snug. Is it dangerous to operate the gun without this "guide pin" in place. Thanks for your consideration.