2014screw, you will be fine. That "payload" number is a manufacturer recommendation, not absolute limit. The axle weights (GAWR Front and GAWR rear are the never exceed limits. The payload number is a conservative calculation to ensure you remain hundreds of pounds under those axle limits.
You have the truck and want the camper, get it and use it. You will certainly want a properly rated (and installed) load equalizer hitch, but a few pounds over that payload number is without consequence.
As long as you are well within the rear axle weight limit (GAWR Rear)and drive sensible you will enjoy that rig for many years without worry.
Load the vehicle as you would for camping and take to to a CAT scale. This will provide actual numbers of the total weight and the individual axles weights.
I imagine weather, road conditions, fuel prices, camp ground availability and other things will provide you with plenty to be concerned about, but pulling that camper with your new truck should not be one of them.
Buy it. use it and enjoy it.