Well that may be a good thing. I thought you already owned the truck. Starting from square one, a 1 ton diesel would be a great choice.
The door payload sticker on a 3/4 T is showing the difference between the class 2 10K GVWR minus the weight the truck left the factory. So the truck you were looking at weighed 7,250 as delivered. You cannot go by the website numbers, as each truck will be different, depending on options. The 1 ton will start out with a higher class 3 GVWR, less the actual truck wt, to get payload. The good thing...it will have a higher RAWR.
Get the fifth wheel prep option on whatever new truck you get!
Jerry