I had a similar deal about 15 years back with a customers 70 Mustang boss 302 And I believe it was Legendary that I caught with their pants down. They were assembling the front seat covers with the backrest pleats 90 degrees out to the bottom seat pleats
So I went to a local mustang parts hoarder and confirmed the pleats were wrong.
When I contacted legendary the guy was like well that can't be
. I said it certainly is
He asked ne to hold a minute. When he came back he said comparing the files to the assembly specs they had been doing them wrong for quite some time and that he would expedite new bottom covers but asked that I no spread it around on the forums which I agreed to until now.
I would occasionally check ebay, BJ, mecum etc and almost all the cars had the pleats flipped LOL