Author Lorenzo Carcaterra has claimed that his book on which the film is based was a true story of his childhood. When the New York legal community went on record stating that no cases resembling the events of his book could be found in any court records, Carcaterra refused to discuss the discrepancy. It is generally believed that his book was almost 100% fiction. Carcaterra's school attendance records show he could not have been in prison for as long as he said, and that he could not have been in prison at the dates given for certain events in the book.
In the end of the movie they sing the Frankie Valli and the Four Seasons song "Walk Like a Man". In the scene where Shakes is in Carol's home (at around 1h 17 mins) he is picking up a record from the shaft of that same single.