I'm glad this thread was dug up. Great looking boat. I have one in the same color scheme, but mine's an 83. I just had the vinyl all replaced, and the stuff i replaced it with matches the color of the sand gelcoat pretty much perfectly. If you haven't redone that seat yet, I'd be happy to share what I used.
Unfortunately, it doesn't have that same "denim" texture to it, but it looks really good!