I just got the scoop on the K30 Burb mystery. Yes they were made but they were not a true 1 ton. They did not have a 60 front from the factory. If you find one with a 60 front it was swapped in by either the dealer or another company/person. They also did not have a 1 ton frame. What they were were 3/4 tons with a 1 ton rating so GM could cover their ass with gross vehicle weight ratings. If you find one in the 80's years it will most likely have a 10 bolt 8 lug front. These were a special order vehicle.