I'd be happy if sparco just made seats for fat people that recline
I'm not overty heavy but at 200lbs, and a 38" waist I don't fit into those Asain mini butt Ricer seats, sigh.....

I've only really seen matching rear seats in show cars, likely sponcered. Have you tried calling sparco direct to see what it takes to get some spare fabric for your shop to cover the rear seat? Also the logo would likely require an OK from Sparco as well.

Else your interior shop may be able to match the fabric close enough for you as well.