Saw the movie many years ago and never saw the play. My understanding is that the movie fit a plot around the songs and that the play was more of a stream of consciousness thing without a plot.
Haj
And this dump in the middle of the thread addressed the factual question of the OP in what way exactly?
The movie was originally a play and it was a METAPHOR It had no need to historicly acurate it was about a pregnant teenage and her clueless boyfriend. But then why am I telling you guys about clueless 
Oh, so the movie’s totally different from the play.