GM Seat Belts (1972) With Tab & Keyhole
I have a 72 chevy with the original type of seat belts where the shoulder belt has a steel tab on it that slips into a steel slot on the lapbelt, and both of those lock into the receiver clip that is bolted to the floor. It's a 3-piece setup.
My question is, what is that type of seat belt called? I'm going to take them out and sell them, and I want to identify it correctly. I don't know if they are called "tabs", or "buttons", or "keyhole style" or whatever.