There's a distributor in oregon that sells factory materials from the '60s and '70s. I can give you the address/phone if you want. They are not cheap, but correct. These are not covers so you'd still have to go to an upholstery shop.
Vintage Auto Fabric: SMS Auto Fabrics The company is called SMS Auto Fabrics, here is their website. http://www.smsautofabrics.com/ If you send them a message through the link on the site, they will send you a sample of the original materials used in your interior. Definitely the way to go if you want to have a factory original restoration. Maria Celeste