I would not go with air bags for a camper. If the truck needs more lift I would add SuperSprings. Cost is the same and nothing to adjust and nothing to break while traveling and they work a lot better as they only engage when the load requires the additional support. The only reason to go with air bags would be if you got a truck with rear coil springs instead of leaf springs.
I would wait until you have the 865 camper on the truck and verify that the factory springs are not enough. This camper has a dry weight of less than 2,000 lbs. and the factory suspension should be able to handle that amount of weight. Most current 1/2 ton trucks can easily manage that amount of weight in the bed.