if you can, go look at it...sounds like a pretty good deal and panels are hard to find. Look for the hidden rust...panels have some spots that are unique (rear fenders, rear doors, drip rail, etc.) compared to the pickups. As stated wiring sounds ok, its looking at the mods that have been done that you mentioned (brake conversion and anything else). Get under it, check it over, take it for a spin. He's a mutt with all the parts from different vehicles put on so hopefully they are all solid bits!
Does seem like the seat bases have some mods as well. And you can always get rid