I remember reading this script on a Usenet Newsgroup a long time ago. I think it was rec.arts.sf.movies. A quick search returns https://groups.google.com/forum/#!msg/rec.arts.sf.movies/XqL... with some comments. It seems like a place called the "Pix Poster Cellar" was selling "a photostat of a photostat of a typewritten screen-play" but the store burned down in 1993.