I've read both and I own both.
The Sabrina book is based off the movie so there isn't that much detail or extras that isn't like the film.
However, the script is a total other ballpark. If it were made into a film the exact way it was written it'd most likely pass a pg.13 to an R rating. I'm going to say just for language...Linus has got quite the potty mouth letting the F-bombs off a few times, lmao. Interesting to read, but it's so unlike what the remake came to be and though now that I've seen the original, it's still far off from the original as well.
15 bucks for the script over at Script Shack
They've got both scripts there.