I noticed the slot in the hinge pin is not level with the flat of the action. I bought a 577/500 Tolly double rifle years ago that was tightened up in England by slightly turning the hinge pin to have a fresh wear point. That evidently is another way to tighten a gun or rifle. Not saying that is bad, just another way to do things. I get surprised all the time with what has been done (or happened to) these guns.