It can get easy to confuse things, as GM has made 3/4 ton trucks with 6 lug wheels over the years. Prewar 3/4 tons were 6 lug, and I believe that '46 was the last year for those (I may wrong about that). With later model trucks, there are 6 lug 3/4 ton trucks in the '88-'98 body style (my Dad actually has an '88 2500 that's 6 lug), as well as some 8 lug 1/2 tons in the '99-'06 body. So your question isn't necessarily invalid.
