71 Dart Front Split Bench
1. I would reach out to Legendary interiors for the cardboard seat-back pieces. They offer them. When I redid my seats, thankfully mine were in good shape and able to be reused because I didn't order them with my replacement upholstery.
2.
SEM vinyl dye is what I used to change color of my headrests from Green to Black. They turned out well but I need to apply their
clear coat product yet to to restore the sheen of the vinyl