I sent the VIN info to the Mack Museum and while they didn't have any info on the military record of the truck they did give me all of the factory info.
They sent me the build sheet, dealer order sheet, owners manual, lube manual, engine rebuild manual, and truck maintenance manual. All free of charge (but they do ask for donations).
The info I got actually provides more questions than answers. Come to find out the truck is actually a 1985 instead of a 1991 as it is titled. I do know the truck only had 861 miles on it when it was sent to Leigh Consolidated Industries in 1991 to be outfitted for the Gulf War. The question is, what did it do from 1985 until 1991 to only accumulate 861 miles? Makes you wonder if whoever ordered the truck decided not to take it and it stayed in dealer inventory for 6 years.
I do know the truck was ordered from Mack of Maine for a customer in 1985 but that's where the info that Mack has stops.