Both of them have VINs, and one is in noticeably better condition than the other (hence the price differential). Both VINs show that they have the 6.5L turbo engine and 4sp auto, which I don't believe ever made it to the HMMWV (I think they're all 6.2/3spd). I'm pretty sure they're commercial Hummers, not mil-spec (do MVs even have VINs?).
VIN Lookups (both are "1998 AM General Hummer Hard Top 2-Door"):
137ZA8934WE182543 12566 mi - nice
2-DR UTILITY, 8 CYL AC PS PB PW PDL AM/FM/TAPE DECK. (LIGHTS & SIREN WILL BE REMOVED AND ARE NOT INCLUDED IN THE SALE OF THE VEHICLE)
137ZA8935WE182535 16670mi - winch looks like a pile of rust
2-DR UTILITY, 6.5L 8 CYL AT PS PB PW PDL, UTILITY BED HAS A SHOWER UNIT ON IT. (REAR HYDRAULIC LIFT, GENERATOR & AC NEED REPAIRS, NEEDS A BATTERY)