I'm gonna have to disagree with the previous poster and several others that seem to have a- "if the engine is not original or matching numbers, then it's 'just another", whatever bodystyle, in this case Dart".
Is a VS29H VIN car "just a duster"?
How about an WS23L VIN- Just another Coronet?
I personally don't care if the motor is matching, but I do place signifigance and higher desireability on cars that were built as performance models- I'd rather have a real R/T or Super Bee with a different motor, than a (just a) Coronet.
EDIT- there should be a smiley for "stirrin' the pot" :)