Chuck Berry is portrayed as being very careful with his money. This was due to being ripped off by club owners in his early days. As a result, wherever he played he refused to go onstage until the box office had been counted and he had received his share. Once he had piled up enough hits he would arrange for the persons owning the venues on the tour to hire local musicians - musicians who learned his songs from the records - and he would meet them right before going onstage and perform without rehearsal, calling out the songs one by one. Afterwards, he would take his guitar and amp, hop in his car, and leave.
Leonard Chess' brother, Philip, was his partner in both the nightclub and Chess Records. However, Philip is never mentioned throughout this movie, and only appears in Chess Records scenes.
Howlin' Wolf is depicted as being very threatening and unaccommodating. Among the great many famous musicians who were his fans, Jimi Hendrix made a point to seek him out, meeting him after a show at a small club. Hendrix tried to tell him how much he admired Wolf's music but was rebuffed. Wolf took one look at Hendrix in his extremely flashy clothes, insulted him profanely, and told him to get lost.
Little Walter was the only person inducted into the Rock and Roll Hall of Fame as a harmonica player. His most notable contribution was that of holding a mic to his harmonica that was connected to an amplifier that was turned up full blast. The harmonica over drove the mic and that signal overdrove the amp, giving it a smooth, fuzzy sound, In other words, he was the first musician ever who intentionally used an overdrive sound.
Little Walter had a hot temper and was in a great many fights, but his death in the film reflects some artistic license. He died from being hit in a spot where there had been a serious, untreated internal injury from a previous fight. This dislodged a blood clot that went to his lung causing pulmonary thrombosis, blocking the flow of blood through his heart. The fact is that the coroner did not find any marks or bruises on him and the initial assumption was that he had died of either substance abuse or of natural causes. He passed away at home inside his apartment at 5402 S Indiana Ave. in Chicago on February 15, 1968.