Have you ever seen any Dart, Valiant, Demon or Duster with a rear window defroster?
Electric grid defrosters were new for 1974.
I have a back glass with one for my 73 Satellite, for a 74 Charger.
The real oddity is the blower in a 29 body A body car.
I've only seen a couple pics of those, and they were on FABO.