AAR rear spoiler for duster
This is who you want for the repro wings:
http://myworld.ebay.com/cnsmoparparts
That trunk groove, looks like he just does the cut himself before shipping. So you could probably email him and have him send you one that isnt cut.
IMO the worst thing about the original ones are the mounting divots. Makes it looks like one of those cheezy bushwacker flares.
I have an mock-up picture of mine. Though i havent mounted it because i have to finish my engine/tranny combo first: