Ski... Ford's specs, with regard to model years, are simply a guide. Since there's no way to know how many biscuit eaters or their gear, are along for the ride, it's preferable to fill up with fuel and head to the scales. Subtract the weight from the GVWR listed on the door sticker and that's what's left for a payload.
Similar guides holds true for the TC manufactures on their base models, sans accessories. You might be able to easily find the weight of some of those add-ons, ie., awnings, a/c, on-board genny, extra battery, etc. and you'll know the weight of propane and fresh water, all of which quickly adds additional weight. Then, it's typical to add another 800#(+/-) for personal gear, camping supplies and tools. Ready to roll, you could easily be 1,000-1,300# over the camper's dry weight. Another trip to the scales with a loaded TC will give you an accurate weigh.
While some suspension mods like Rancho 9000 shocks, sway bars, air bags will enhance handling, they won't increase your GVWR.