Yep,definetly a M211,looks like it may have had a winch at one time(inverted bumper and no center splash shield) looks to have at least 1 M135 wheel on it(right front) backspacing looks different from a standard M211 or M35 wheel.
Also looks like it has a civilian hardtop on it,$2500 is about $1000 too much for a GMC in that condition unless it's in drive away shape in my opinion.