Very cool. I have seen those before too. It is a 3/4 ton rating, which for the military is usually underbuilt. The 3/4 giveaway is the number of lug nuts. 5 with the 9 x 16 tires, iirc, is 3.4 ton. I has a M116A1 flat bed that I loved, but had around a few years and never did anything with so I sold it. Probably never should have, was a hell of a trailer.
Anyway, that is neat. Total military style, layers and layers of paint. It is a hell of a platform to start with too..
Here are pics of the M116A1, probably the same manufacturer..