I’m not a big Tarantino fan, but I really liked this movie. I agree, it’ll ring truest with folks who were in high school and college during the 60’s.
It’s rather a parallel-universe Hollywood. Things are what they were, only more so (as befits a Hollywood movie) and not _quite_ as you remember it.
I was not in HS at the time, only a kid but one of the reasons I loved this movie was the music but also the depiction of Southern CA during the time. It was like Tarantino had access to a time machine. Brought back a lot of good memories for me.