For a value range, for insurance purposes, the "Classic" section of
www.nadaguides.com can do that. Values which basically align with "The Old Car Price Guide", but a little different way of classifying the various levels of condition.
For the seat fabric, seek out an "old line" trim shop that has the "DeLeo" or "Detroit" fabric swatch "parts books for fabrics/upholstery". These books have the original swatches AND part numbers for the OEM seat upholstery. Vinyls and the fancy brocade-style fabrics used back then.
In some respects, it might be best to re-use the vinyl sections, just replacing the fabric portions. Notice, too, the French seams that Chrysler used and be sure the shop replicates those. A more expensive and better way to do things.
Unless you find some "new production" fabrics, then the fabrics you get can be "NOS", which means they are the same age as the car, which might also mean a certain amount of dry rot is at play (although they look new). Similarly, the "oils" in the vinyls can evaporate with age, making it more brittle. Some coatings/refurbishers can help prolong its life, but not a "protectant" per se. But do start with a good cleaner that cleans and conditions it. So you might inquire as to the age of any fabrics your shop gets.
Reason I mention the "age factor" is that in the '80s, a friend had a '66 Cadillac he was using as his family car (with two small kids). He wanted to keep it "stock", so he went to the trouble (more back then than now) to get the orig fabrics for the seats. When it was done, it looked good. A year later, it was in pieces. I asked "What happened?" That's when he mentioned the dry rot situation. So, having seen that, that's why I'm mentioning it.
As a note on shopping for an upholstery shop, you might inquire with new car dealership service departments in your area to see where they send vehicles for warranty replacement upholstery repairs. This can ensure that the shop knows what OEM Quality Work is and can do it. Even if the dealership orders in new ready-made covers, they still have to be installed to look like when the vehicle left the factory. Same if they do a "panel replacement" too. Might look for a shop that does "leather upholstery upgrades" to non-leather, late model vehicles, too. Key thing is that your results look "like it left the factory yesterday" rather than have wrinkled seams and such. This search might take a bit, so don't hurry.
Take care and make the car look as good as it can. The time and effort will be worth it.
Enjoy!
CBODY67