No Dusters ever had the single scoop with twin snorkles. They were only available OEM on '72 Demons, '73 and possibly '74 Dart Sports. Not sure about the '71 Dusters having the 2 seperate scoops. There was a Twister option, I believe, that had a pair of small, non-functional scoops.

An aftermarket scoop I got has rear center and front center studs that aligned with existing holes in the underhood bracing. I believe OEM are the same.