1976 Duster - Slant 225 - 4-speed stick

is this a Feather Duster ?

I am not sure. It certainly didn't have the "Feather Duster" stickers when I got it. It does have a few of the attributes (although the carb & intake have been upgraded as noted).

Does anyone know if there is a way to identify a "Feather Duster" by VIN number, or other solid method?