I have a 1972 Sportsman with a gvwr of 8300lbs. I see that there were three rating options available then. 7000lbs, 7700lbs, and 8300lbs. Was the only difference the number of leafs in the rear springs being 5, 6 or 7 leafs?
Welcome to Allpar. I believe that there were front axle weight rating and tire load range rating (E) differences also. The 1 tonners had 8-lug 16.5" wheels.
I'm moving this to the 'Vans and A-series' section for more visibility. http://www.allpar.com/trucks/b-vans.html