Factual error: When The Oneders are recording their song with Uncle Bob, there is an In-N-Out cup sitting by the recording equipment. There are no In-N-Out restaurants in PA.
Factual error: When the boys go to the radio show in CA, the DJ says to the listeners to keep Saturday and Sunday, August 20th and 21st [1964] open. The 20th and 21st of August 1964 were a Thursday and a Friday.
Factual error: Several times during the film a Zildjian stencil logo can be seen on the bottom of a cymbal. Zildjian did not start applying logos until the 1970s.
Continuity mistake: In the scene where Faye and T.B. Player burst into the appliance store to announce the song was on the radio, watch the blue car behind them. It moves forward twice, depending on the camera shot.
Factual error: In the scene where Ethan Embry is taking a picture with the Marines, Mickey, and Goofy, the Disney characters are modern characters, and not wearing the same style costumes that were worn in the mid 1960s. When the film was set, the non-black part of Mickey's face was not as round, the bow-tie was orange and had streamers going down the front of his shirt, the collar on his jacket was more fancy and white. In the 60s, Goofy had a larger head, a blue hat, and a green vest. He also had eyelashes which have since been removed from the costume.
Answer: I don't know about the script, but the song was definitely an original - and nominated for best original song that year.
K.C. Sierra