[abaucom21]

As an Interior Designer I have some experience dealing with conservation of very old textiles on high-end antique furniture (but no experience dealing with 1960s vinyl which is not the same chemical makeup of 21st century vinyl). You will have some issues just replacing a single panel. To re-stitch (re-sew) a new panel your upholster will need to reinforce the underside of both new and old vinyl panels so the new stitches will hold.

To perfectly match patching in a new material with an aged material, think you might need to do a national search for a firm that specializes in furniture textile restorations and that is going to be expensive.

After your time / effort, & material / labor expense to "Conserve" your original 51 year old vinyl upholstery, it might be best in the long term to reupholster both front and back seats with a more cost efficient upholstery kit. What would be your next move if a year from now your 51-year old vinyl tears at another seam? Start the process again to replace one degraded seam panel at a time? Rear seats on our autos where typically not used. So if you have an upholstery seam fail over time on the back seat, shortly you might have front seat upholstery seam failure. Yes, the seam threads do degrade over time.

I bought my 1966 convertible a few years ago, granted it has black interior and the black color is not as exacting as yours. The interior was reupholstered in 2001, still looks factory fresh and vinyl still soft 16 years later.

Think long term: A patched interior will not necessarily add value to the auto unless the rest of the auto is 98% factory original, correct from 51-years ago. Do you intend to enter your Bird in a 'Survivor Class' at national shows or do you want an exceptional looking Bird that you can drive on weekends?