It is a jukebox musical, and I suppose that's right when you put it that way. That said, the music's actually more creative in places than I was expecting; it's not just "and now, here's this song you remember, just the way you remember it", there are scenes where two or three originally-unrelated songs are woven together to reinforce or counterpoint each other.

I have a fair few books that predate ISBNs, as well, but at least you know where you are with those. The 9-digit SBN was intriguing because it was clearly related to an ISBN without being a close enough relative to be usable as-is.