It looks honest, as in original and not screwed about with. But sitting in a shed 21 years, brakes will likely need attention as will cooling system, rubbers etc.. need a good going over in other words.
Body work appears sound in photos. Have to see it in person really. If a solid car in my opinion $20k is reasonable. But others balk at 2+2s priced that high. However history will prove me right I'm sure and I like the 2+2s. Especially on the open road.