New to the board, and I know this is an old topic but, I need some insight please. This board has been the most helpful. I’ve been presented with an 1964 to 1968 500A with no serial. It had the red extended butt stock pad, the scalloped bolt, great shape, wood, and bluing is all really nice. Bottom line, what are one of these guys worth, and durability being how old it is? I’m new to the shotgun world, and I appreacite the help!