Basically the Demon was created for Dodge for the 71 model year by bolting on the 70/71 Dart front fenders, hood, grille and front bumper to a Duster body.
Meanwhile, the Scamp was created for Plymouth for 71 by bolting on the 70/71 Duster/Valiant front fenders, hood, grille and front bumper to a Dart Swinger body.
You can sell much of the rest of your Scamp parts to Dart Swinger owners. I believe the rear bumper on the 71-72 Scamp was the same as the 70 Dart rear bumper, but the Dart rear bumper changed for 71-72.
So I agree, the answer to your question is yes.