In 2001, Jeremy Davies was in preparations for a different independent film about Charles Manson. He made a tape for the filmmakers of himself playing Manson and the tape became a popular bootleg in the industry. CBS cast Davies and allowed him to rewrite his lines due to his performance in the tape.
Mary Lynn Rajskub originally auditioned for one of the victims before she was cast as Lynette Fromme.
According to the book by prosecutor Vincent Bugliosi, Charles Manson carved the X on his forehead while in prison for the murders, and several of his copied this act. He changed the X into a swastika, and his followers again followed suit.
In this "Helter Skelter" film, Manson is shown with an "X" mark on his forehead. In real life, Manson wore the Nazi Swastika tattoo on his forehead. During the trial, he carved the x to represent "his being x'd out of society". It wouldn't be until sometime later, he turned it into the swastika.
Jeremy Davies and Alison Smith were both born in 1969 in the months following the murders. Davies was born in October of that year and Smith was born in December.