With Alembic finishes, there was a change, -and I don't know exactly when this change was- from a Sherwinn-Williams product called Polane to another compound of Poly finish. I suspect it is sometime between Jazzyvee's '80 short-scale, and my '80 medium-scale though, because it has that silky, velvety smooth, but not super glossy sheen. I love that look and feel. It's just a bit more shiny than what I'd call satin. My '81 and '85 Distillates were the same way. But the older '77, made within days of the subject guitar of this post, has these tiny inch-long horizontal checks interspersed all over the body. It's very mild, but I've seen some (like Jazzys, where it almost all flaked off. Others seem unaffected. No idea why.
I read one time (maybe here) that Sherwinn-Williams altered the makeup of Polane at some point, and the change made it unsuitable for use anymore.