Not an a-body but your opinion on worth...

From the pics it looks as though the body is pretty decent although there are trouble areas that don't present themselves unless close inspection. The rot above the windshield would dictate a possible long term water leaks that affect the cowl sides and may already be underway in rotting the floors from standing water. The body side mouldings can trap dirt and moisture against the body that cause rust if not checked. Inspect the wiring running underneath the box to the tail lights especially rear taillight wiring harnesses and sockets for degradation. Chrysler wasn't using the plastic wire tubing covering yet. Everything was tape wrap and the tape would dry out and turn to powder. The wires going into the sockets would just rot off.

The wing windows don't seal that well which lead to leaking. Check condition of the brake and fuel lines for rot. Axle fluid leaks around the hubs are common as are worn axle shaft u-joints and steering gear leaks. Make sure the 4 wheel drive engages properly in Hi and Lo and that the transfer case is functioning. Selling price has alot to do with whether the 4 wheel drive is functioning properly. If it isn't, you'll be sinking some bucks into those areas to get it back into shape.

I sold my 87 W150 in the fall of 07 for $1350. Got snapped up right away. Had 213,000 on it. Original 318 and tranny never rebuilt. Ran great. Had it for 18 years and just took good care of it. Body was in good shape with minimal rust, unusual for these parts. Rot box 4x4 1st gens around here go for 3-500, decent ones top out at 15-1800 although I've seen southern, rust free 1gens sell for as high as 25-3000.