Too many variables, I remember when my friend at engineering school told me he had to base his final thesis on "butterfly effect" which he had to explain the effects of wind generated by wings of butterfly in TX relation to starting a tornado in OK. (I probably can't even put that that well)It also depends on the thickness of steel he puts on the truck. A square foot of 1" thick AR500 weighs in at just about 40.5lbs. You can do some math to figure out the weights of the other thicknesses, then multiply the weigh by how many square feet you put in.
Of course, he also modified the cab extensively so the bed volume goes down reducing the likely payload to be carried...
I didn't become an engineer.