The designation for the body of the truck is "Shop Equipment, Contact Maintenance, Truck Mounted" or SECMTM. The contents varied by the type of unit it was assigned to. Those are listed in Supply Catalogs (SC) depending on whether it is for a maintenance unit or any variation of an engineer unit.
The 1438th Engineer Detachment at Camp Grayling had 4 units assigned to it, but our CO never let me put through the request for the complete tool sets for our Carpenter, Electician, Maintenance and Plumber sections. They didn't automatically come with the truck like the BII did. Ours were mounted on the M1031 Chassis, but that didn't show up anywhere in our maintenance records.
Edit: Ours had the PTO driven generator, and we had to relearn how to set it right every time we used it (which wasn't often). They did work well for running the lights in the GP medium on annual training.
I also wanted to move the air compressor from the back left side of the rear compartment to closer to the cab with a protective screen, because I knew the guys using the trucks liked to just open the doors and throw stuff in. Not laid out the best for packing and stacking gear and equipment for field use.