I have decided to mount the corner jacks on 2x6 and use that to leverage the camper off the truck. Haven't actually done it yet since I have to unbolt the camper from the truck bed. Back in the 80s they did not use the tie down method, at least not for this installation, they bolted it directly to the bed of the truck. I have located the bolts but have not had time to pull it off the truck yet since I wanted to make a base to rest it on so that it would not sit on the ground and get wet. My garage is too full to store it in there and I wanted to do a complete redo of the interior and electrical before I put it on hopefully a tundra with a long bed. When I do, I will post the results.
I decided to go this route because the older campers do not have the corners braced for corner jacks. So when I strip it down, I will brace the corners for the jacks.