No biggie.. I didn't even know there were 2 different snorkel scoops until I bought the wrong one for my Demon and it didn't sit right.. That's how I found out. There might even be some modification that needs to be done if putting on the Duster. Never made for the Duster...just 72 Demon and Dart Sports.. Again, I could be wrong.
I was thinking the same thing about snorkel on duster...not offered. Found out about difference same way you did. Duster has 2 ribs shaped like tapered wedge. Scoop would need modifying.
