Factory assembly manual shows 37 welds on the back panel and no bolts, but I know how things can change when they are actually built. If I were doing something like this I would get a sawzall and cut across the back of the cab below the belt line seam on the 5 window so you can easily clean it up for installation and cut across above the beltline on the top you are replacing. Look for a weld at the bottom of the front pillars to cut loose and reattach in the same spot.
