Have you actually weighed the loaded tongue weight of the camper? Size it according to the actual loaded TW to be equal too or greater.
Unless you weigh it, you really do not know how heavy it is. It could be over 15% or under. My prior 7,000# GVWR rated camper had a 20% loaded TW.
Dealers have been know to supply a WD hitch too small for a loaded camper floor plan. The day it left their shop it may have been OK. Then you start loading it and it can then be too small. Unless they do some kind of study on actual loaded TW campers per floor plan by know their customers who use them, they really have no idea either.
If you find your loaded TW requires an upgrade in hitch size, make sure you check the rating of the receiver on the truck that it can handle the upgrade. Also check the rear axle rating on the truck too.
Every time a camper and truck is weighed there is often a surprize, wow how did it get that heavy? Darn stuff just plain adds up...
Hope this helps
John