Yeah, I saw that via another forum. You should check out his G-15 restore; it's epic. That LGP-21 looks almost pristine, and based on the back story, they guy who originally had it sounds like the kind of guy who knows how to store vintage kit. That thing didn't come out of a barn someplace, so not surprising the coatings survived. :-)
https://www.youtube.com/watch?v=IBjh0SaA5dc
https://www.youtube.com/watch?v=39SwIl3wQDw
The coating wasn't a problem, it was a couple of the heads that sort of failed.