My doors were stripped out when I got car. They are now together except I don't have anything that makes sence to screw arm rest to. Nothing in boxes of parts fits the door slotts. My guess is they were thrown away.
You want three V-shaped pieces of metal with screw holes in them (kinda hard to describe these). These things fall out very easily - you may want to look down inside your doors to see if any of them might have fallen in there. I think these would be the same as ones used in Mustangs, and they should be available from most parts vendors.