An F350, even an SRW, of that era would be adequate to haul that camper. If the F450 is a good deal, I would not worry about "overkill." Don't buy it because you think you need it. Buy it because it's a good deal, or because you have plans to move up to a larger heavier camper in the near future.
The only concern I'd have is with camper fitment. Truck dimensions have changed since your current truck was new. Bed openings are narrower. Bed sides are deeper. Cabs are taller. Odds are you'll need a platform to raise the camper enough to clear the cab of the truck at the very least.