Early A-Body Interior Rear-View Mirror Repair

Welcome to FABO. That's a nice looking little Dart you have there! Laysons Restoration has headlight rings for it. Granted, they're proud of them.....but they look nice! @Rick@Laysons might be able to help.
https://www.laysons.com/Catalog.cfm?nCatID=1033&nModelID=5&nModelYear=1964If you've fooled with other old cars, you may already know about SMS Fabrics, which is the go to place for finding original pattern upholstery material. They may have what you need to fix your seat.