You are most welcome.
Since I have not seen photos of the other Hiawatha you describe, I can't comment. I also can't go to links. You would need to either post here or send direct to me, then I can see whatever it is you are describing. Show me... then I can tell you more. But gotta see it.
And remember there were numerous models of Hiawatha each year, not just one. So just because frames differ does not mean this jumps the year. Also remember that there were numerous retailers that sold Hiawatha, not just one as some believe. And there were also promotional sale models of Hiawatha. So, unlike hobby DIY experts will tell you today... a Murray-made Hiawatha is not merely a translated Murray brand bicycle in different graphics. Lots of differences big and small. And then, lots of years on top of that.
RE: Hiawatha middleweight graphics... Don't be too fast on trying to replicate on your own. Some of these new-age graphics guys have gone bonkers making stencils, decals and appliques– even when they don't know what they go to. Or only think they do. So what you need may already exist. Check around... and don't expect the sellers to know model names and years. They usually don't.
RE: Corvairs and Harleys... Had both but sold them decades and decades ago. Had a girlfriend once who had a Corvair convertible and then I bought myself a Corvair Corsa convertible. Had lots of very rare stuff on it, including very rare real Dayton wire wheels (even experts don't seem to know this was a factory option once). I saved some of my brochures and factory 8 x 10 glossy photos. Presently working on a big history of Corvair-based concept cars. So I know a bit. But thanks.