Just had someone interested but on checking top tube length he had this to say about the size, which sounds sensible:
"Sad to say, I think we have to pull out because 20.5" is also top tube length on her current bike (1994 16" Hahanna-just measured it), so it looks like it wouldn't be any bigger.
Digging a little deeper, I had a look at the original catalogue on konaretro.com, and it seems there was only 16,18,19,21 sizes offered, no 17". I would hazard a guess that yours is 16" but there are more dimensions in the catalogue you could measure it against to check.
I know there are some geometry differences on the early frames.
Good luck with it, and please don't split it, it's too good for that!"