I understand better now. The black and grey pinstripe will be difficult to find, but I'm sure it's not impossible. I'm going to look through some AMC sources, because the pattern may have been used prior in a Rambler American. AMC liked to recycle ideas from time to time.
Update; I have searched around, and have come up with a close substitute, but will continue to look.
https://smsautofabrics.com/collections/vinyl?page=57 1962 Buick The stripes are not the same width as your original, but would look alright in a pinch.