Stock 64 dart fitment

yes, I'd say 99%. The 64 Valiant Barracuda had:
An extra Valiant script under the passenger trunk lip
slightly different bulkhead connector (3 groups instead of 2)
a different dash layout and a Dart-ish round button radio.
No 'S' option in 64
No 4BBL option in 64
No push button trans option in 65
interior seat pattern...
...anything I missed?

Your Dart mechanicals are about the same across family lines too.