IIRC, the 320iS was only made for two years but the sport seats were available as an option from introduction in the USA for the 1977 model year. The earlier ones didn't have the emblem though. They're great seats, I have had them in lots of 2002s. A direct drop-in if you have all the parts from the E21. I have one as a passenger seat with a "real" Recaro on the driver's side in my '76 2.3L 2002. Three more spares in the basement if I can find them, for future projects! Never paid a dime for any of mine so I can't tell you what they're worth. I can tell you if the bidding gets much higher, I might have to pull mine out and clean them up for Ebay!
The 320 seat sit high if I reminber right, check out 20002faq.com there is a guy that rebulids them out of Canada and does a good job. 610.00 buck for seat that may need work is two much
The 320i sport seat sits rather low, actually. I don't doubt the stock E12 seat sits higher than a worn-out 2002 stock seat. But a lot depends on whether you're comparing lowered sunroof seats, shot spring pads, etc. My 320i Recaro Sport seat sits about the same height as my Recaro LN. Many confuse the FlowFit seats commonly found in BMWs here with the E21 sport seat and there are those who offer the FlowFit reupholstered for the 2002, too. That seat is a cheap copy of a Recaro in many ways and sacrifices several inches of headroom in the process. I'm not able to fit in a 2002 with FlowFits yet I have inches to spare even with a helmet on in my sunroof 2002 with the Recaros, both "real" and E21-style.