Here are the ones I make for F's the orange one is an original. I get $250 plus shipping. As you can see they are dead on! I'll try one on a Duster maybe this weekend & get a pic. If anyone has an original to loan I can do them!
Volare / Aspen spoilers are different. On an A-body the trunk curves up at both sides where it meets the 1/4 panel. The F-body is flat across the trunk and 1/4 panels.