Typically, there are 8-bolts that tie the bed to the frame mounts. The mounts welded on the bed itself are sheet-metal. My point was/is, those bed mounting points frequently split. I have looked under many pickups, and rarely do I see one that does not have more than one cracked. You can reinforce the frame, but that is not what fails. I have never seen a 5th wheel plate that mounts to the sheet metal of a pickup bed only. Doesn't mean there is not one, but I have never seen it. All I have seen, sandwich the bed between the plate and frame mounts, but not bed only.