As Richard said, just GS. We had 12KJ49 and 12KJ50 in the WKSP MT, used as runarounds for the stores section, or to ferry the ASM or OC some where. Great fun for a young spr, sitting in traffic and rocking from side to side as you revved the V8...
I have a memory that there was some mod done to the front brakes, but can't remember the exact details. The gearboxes didn't last long (LT85?) and you would often hear one whining it's way around camp.