Can anyone tell me why numbers would be stamped on the inside of the drivers side door post on my 1966 GTO? I am reconditioning my 66 goat and was checking the condition on the area inside the left speaker hole and found seven verticle numbers. I know the area I saw is behind the VIN plate because I saw the back of the rivets and the numbers are stamped to the right on the outside wall. I was told there are hidden ID numbers on classic cars but never thought about it until I found this one. Does anyone know what the numbers are for? I would appreciate any information.
