the differences in rear spring packs was the main variable that set the GVW, along with wheel/tire combinations, a 1T could have a GVW from 6200-8800, check the shop manual or glovebox manual specs .... and there is no such thing as a "2 ton
cab", the cabs didn't change from 1/2T up, it's the complete chassis [not just the frame] that determines the model designation, again
check the manualsBill