The current Old Cars Price GUIDE says a #4 is worth $5400 and a #3 is 12,150 for a half ton.
From your description I'd say it is not a #3 for sure but perhaps better than a #4 (close to a #4) so somewhere between that range is probably a fair price....that's quiet a range but condition is everything....and how bad you want it.
Good luck, take your camera and shoot us a picture if you can?