I have for sale a set of front and back new seat cover for a 70-71 duster. I purchased these for a 70 duster I'm restoring only to figure out I have 73 bucket seats. I paid $355 plus shipping but I'll take $300 shipped to anywhere in the lower 48 states. Located in wisconsin.
Just an FYI, if you are planning on replacing the buns and not worried about being year/model correct, you can purchase the buns for the seat covers you have. The seat frames are all the same.