I sanded the body filler I placed on the cab floor, body filler seems silly because it will be covered with carpet but why not. I also flipped the cab and started on the bottom. It is in really good shape, no body filler will be used here. Not sure where the rear mounts are, the ¾ ton Chevy cab had some type of bracket on each side and the GMC ½ ton has some sort of center attachment device. Neither seem to match the TCI frame, more research is needed.