Hey Blaine, I got home and dug it out and realized it's actually a very early /6 seat. Even has the plate on the back saying it's from an R90 /6. I think that could come off though and if I remember right the LWB /5's still had very similar seats. (?) I'll link some pics here and if you're still interested send me a message. Note, bottom does have some rust and there's no hinges. I just set it on my bike for one photo so you could get an idea of the look. Either way, best of luck with the project!