I suspect the script used by this community theatre in 1991 is Barrie's 1928 final version, which they would have got from the theatre agents Samuel French when they obtained a licence for their production. They probably meant that their production was based on Barrie's original play (as opposed to the many adaptations, musical or not), but not necessarily the same version as that staged in 1904.
The earliest script (or draft) is dated 1 March 1904 and is held by the Lilly Library at Indiana University. Search for "Anon: A Play" on the database here for the complete text, which Andrew has transcribed. I believe the Beinecke Library holds the rehearsal script of the 1904-05 production.
To get an idea of the differences between Barrie's original staged version and his final version first published (rather than licensed) in 1928, the Peter Pan Keepsake* first published in 1907 by Chatto & Windus, is your best bet: it was novelised by Daniel O'Connor from the early production (later published by George Bell & Sons under the title The Peter Pan Picture Book with illustrations by Alice B. Woodward).
* I'll scan my copy and upload it on the database in the next few days.