I have a Blue/Black FC seat in the shed, the stitching is coming apart all over the place including the pleats, but if it helps I can strip the covers off and send it over
The rear seats were part of what looks like a failed vinyl painting experiment though.
No matter what you do with the old seats the stitching will always be an issue due to age, sooner or later it will deteriorate. Getting a modern vinyl equivalent is possible but it will never be a 100% match.
If you are handy, I have been selling seat cover sets and door trims with the correct vinyl welded patterns and it will cost a lot less than $3000.
Check out stapla's build for an example of the finished products
http://photos.byh841.com/GalleryFilmstrip.aspx?gallery=341778