I also picked one up, works nicely. The unit appeared unused with the new manual inclosed inside.
The difference is spelled out on page 27 of the above linked pdf.
The basic difference is the plugs on the cord, and the Army version has a starter for the fan motor which incorporates a big wirewound resistor for reduced current during fan starting. The manual says that the Air Force (H82) version cannot be started on a MEP-016b/701a generator, and I tested and found this to be true...trips the breaker right away.
Nice units though, if you have not picked up your unit yet, it may have the manual inside of it...mine had both, still sealed in plastic.