Hy Gene_Spartan80, those are multi-piece Dayton wheels which were standard equipment on your truck. These wheels are completely safe if handled correctly, never inflate a deflated one unless it is in a tire cage. The wheel is the heavy cast part in the center the multi-piece rim with tire attached is retained by the five clamps at the end of each spoke of the wheel. The rims on the rear have a spacer in between them and both rear wheels can be removed when the nuts and clamps at the end of the spokes are removed. A word of caution about the rear wheel clamps, they can get wedged in place under considerable pressure, just loosen the nuts a couple of turns and then pry or hammer on the wheels until the clamps release, then you can take the nuts all the way off and remove the clamps, outer wheel, spacer and inner wheel, hope that helps.
