Words ranging from "entry level" to "cheap" are typically used to describe the construction of the Palomino brand. They're definitely not designed for heavy abuse, but if you use it like you own it and take care of it they hold up just fine.
3400lbs is just the beginning. You also have to add in the weight of options and anything you will bring with you on your camping trip, including yourself.
Will it be too much for a F350 dually? Probably not, but you might want to take the truck and get it weighed empty first just to see how much payload capacity you're starting out with.
You may exceed GVWR, but you should be under your axle/tire ratings with upwards of 5000lbs of camper, stuff, and people on board with that truck.