The previous owner threw out the driver seat bottom (rails and everything) as well as the driver seat back. I still have headrest thankfully. If you can help me on these 2 parts, message me here or better yet, email me at Honda600Performance@cox.net Thanks, Rick Morris Broken Arrow, Oklahoma 74014 (use this to calc shipping).
You may want to check with Mike at Super Mini trucks in Tishomingo Oklahoma. He had a Sambar he was selling parts from the last time I was there. https://www.superminitrucks.com/
I have one. Not sure on the condition of the material, there is a crappy seat cover on there. If you are still looking for one let me know and I will pull the cover off. Mine is from a 1992, I suspect they are the same.