donn, fist thing, these fifths have the rubber suspension, so there are no "spring hangers" on them.
Also, you didn't even read the original post. His truck box is 59" high, and the camper is 57". So even if the truck settles 3", with a minimum of 6" clearance, that still means the camper is sitting 5" high in the front. While not unmanagable, it might affect the way the fifth tows.