Reading: Script - American Beauty

The first full script I read was for 'American Beauty' from 1999, directed by Sam Mendes. I have not seen the film in a couple of years, so I didn't remember the story well enough for the script to be uninteresting. The script was written by Alan Ball.
I'm just starting to get familiar with the screenwriting format, so this was useful to me.
I had to use a Screenwriting Glossary (http://www.screenwriting.info/glossary.php) for reference while reading this, as I didn't understand much of the terminology yet, especially abbreviations, being very new to the form.
Ricky is 'O.C.' which means:

O.C.

Abbreviation for Off Camera, denoting that the speaker is resident within the scene but not seen by the camera.

The character descriptions were very brief, usually just mentioning the colour/ style of hair and their general demeanor.

As I was reading the script, I also had some of the scenes playing on YouTube to spot the differences between the final draft and the actual film. There were many differences in the action but not in the dialogue. For example, in the scene at the beginning in Ricky's bedroom, Jane is written as being naked, smoking a joint and twirling her hair. In the final scene she is fully clothed and resting on the bed, looking more upset than relaxed. There were so many differences that it made me think perhaps, it was not a final draft that I was reading, but a first or second draft with more revisions to happen later. It was interesting to note all of the changes that were made and try to understand why those decisions were taken by the writer/ director.