Say... WHAT?!

You're not wrong.

A Demon is a "duster ***-end" with vertical slit tail lights and a 70-72 dart front end.
A Duster is a Duster period, you can make a "demon" clone by swapping the front fenders/hood/core support/bumper but everybody is going to know it's a duster (any mopar guy anyway) by the tail lights being across instead of vertical.
A Dart is a Dart.

Ok, now my real beef is hood scoops. People LOVE hood scoops, so I have absolutely no clue what year those types of scoops were offered and what models...... seems like they're on every dart/demon/duster -- either those or the duals made of metal.