On our 66 Suburban, it had it on the drivers door, but not the passenger door. I am adding them to the Passenger side, and there were no weld nuts behind the cover. You can buy the weld nuts from an aftermarket parts supplier. I believe I got mine from Orange truck and car shop in CA. You will need to transfer the hole thru the side cover. I think there are dimensions in the service manual. You can probably get a decent arm rest from one of the parts sellers here in the parts for sale forum.
