JRscooby,
Your question, 're gcwr being less than gvwr has been in my brain since said truck out pulled a rig with double the gcwr. I soon learned as I think mentioned earlier, or on a different thread, depending how speced, a truck may have a gvwr equal to gvwr. Then depending on if the truck drivers is setup for local vs over the road duty, the drive train may have different setups depending on how being used. The 3500 was great on a freeway, horrible for local steep slow speeds on hills. 2500, excellent for slower speed, steep local roads.
More than one way to look at how a rig can be speced for same weight.
Marty