Ron, I sent you an email reply elsewhere, but for the benefit of others find a good custom upholstery shop that can de-stitch the affected panel, cut a copy, and reinstall it. You''ll probably save a few buck if you can pull the seat bottom or back yourself and present them with a less labor-intensive job.
The only possible hiccup is matching the colors. I had a dye job done on one seat in a '79 that was an absolute horror, so chose the upholstery shop with care (in other words, good work cost bucks ;-)
Rgds,
MWR