Yes I think that's what I was finding out. Factory tires being the weak link. I believe I will buy the F350 I found and change out the tires. "Should" be good for close to 4020lbs payload, with the proper tires.
Looking at Fleet Ford specs shows the weak link is 3590 lb capacity for their OEM 18" and 20" wheels.
For years tires were the weak link with 16"/17" tire capacity. Truck mfg turned to 18" and 20" tires, when GAWRs started up, that may have 3750-4000 lb ratings so their no longer the weak link in a OEM suspension.
Taxable weights ?
Means nothing in a state like my state... Oklahoma. We have no weights of any kind to register our non commercial vehicles. A GVWR or GVW on a out of state vehicle registration simply isn't used.