What has happened to this bed was somebody totally eliminated the entire floor and welded and bolted in the floor from a more current truck. My question was what the mounts on the rear of the bed were from. But I think those were also welded in by someone else. So I think I will have to completely fabricate the mounts from the bottom of the bed, to the frame rails. I am going to use this bed as-is. With a lot of work to it of course.