I retrofitted a Post '85 (i.e. - Handles in the cowl, not in the seat) tail cowl on my '85 RS.  Seems every seat I've seen on eBay doesn't come with hardware, which is fine, except I noticed there seems to be differences between hardware mounting on at least the Corbin and some of the OEM seats I've seen.  My Seat:





The seats I've seen that would fit the Post-'85 cowl, that rear hinge mount is Diagonal, not straight, and the front hinge mount is on two bolts, not three.  Do I just need to keep looking for a Post '85 seat *with* hardware?  Or is there another retrofit option I can use with my existing Corbin hardware?

Some components of 86+ seat mounting hardware are different from 85.

85:
https://www.realoem.com/bmw/enUS/showparts?id=0513-USA---K589-BMW-K%20100%20RS%2083%20(0502,0503,0513)&diagId=52_1006

86+:
https://www.realoem.com/bmw/enUS/showparts?id=0513-USA---K589-BMW-K%20100%20RS%2083%20(0502,0503,0513)&diagId=52_3683


86+ seat hardware:



Linked below is a page for doing a low to regular seat conversion but if you scroll to the bottom of it you'll see what hardware is required for 86+ seat mounting. You'll notice that the 86+ seat hardware does not have the big rubber blocks on it like the 85 stuff does.

Scroll down on this page to "Seat Mounting Hardware"

http://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/regseat/regseat.htm



I have 86+ seat hardware available.

This helps a lot, thank you!