Is this Duster overpriced?

It's pretty rare for an A Body to go for over 30k

Note that 30k (U.S.) converts to over 40k (CDN) and, just go to cars-on-line.com to search and you will often see the one or two A-bodies that are listed (and often sold) for over 30k.
Compare that to (especially 1970) E-bodies - which are definitely not as rare as the (H or L-code) A's.
Important to maintain 'originality' - especially with body color and engine - IF you hope to get 'top-dollar'.
Remember, ANYone with deep pockets can create a 'clone car' but it takes a real man to restore one. (no offense intended) - anyone.
If that (orange) Duster was a 318 car, it could still be worth between 15 and 20k, in perfect condition, but as a 340, that could move up to between 20 and 25k. And, one of the rarest of all would be a '74 (Dart/Duster) with the L-code engine AND - - D21 trans.