MY340 had one of the nicest 340-sunroof-fold down cars in a great color combo around and the selling price was nowhere close to 28K IIRC. 28K is REALLY nice 70-71 duster/Demon 340, 4 speed, great color combo price territory.
This one sounds like a project needing some serious metal replacement. I have a Dart Sport 340 sunroof/fold down and haven't been able to sell the shell that is in real good shape for $800.
If it's a 4 speed car I'd be surprised if you could get 4K out of it with all the spare parts.
Good luck with your sale.