Caesare's rise to fame is charted through a montage of various magazine covers dated from May 1961 through October 1961. However, later in the film, Caesare arrives to play in Nashville and a banner reads March 17, 1961, before any of those magazines would have hit the stands.
After Caessare's first successful concert, there is a montage of magazine covers. The only date showing on those issues is July, 1961. Caeasare is then in seclusion for several months, before finally putting on his second appearance in Memphis. The banner above the venue however, announces the second concert occurring March 17, 1961.
There are two scenes in the parking lot of the club/bar where Vincent went to see Tommy play saxophone. The first one is where Vincent tells Tommy he would like him to record his songs. The second one is when Caesore is puking after running offstage at his debut which took place two years after the first.The cars in the parking lot are the same cars parked in the exact same order in both scenes.
Before Guido's first gig, he and Tommy are in the dressing room, with Tommy smoking. Tommy talks Guido into smoking. The book of matches is modern. Matchbooks used to have the striking strip on the side that opens, directly below the matches. Unfortunately, sparks, similar to the one that flew at Guido, could have landed flown into an open book, causing all the matches to burst into flames. In 1973 a law was passed, mandating that the striker be placed on the back of the book. The matchbook Guido lays on the table does not have a striker on the side that opens, making it out of place in the early 1960's.
The body style of Vincent's Ford Thunderbird was produced from 1961-1963, with slight modifications. The car he uses is the only model with 3 chrome accents on the side, dating it as a 1962 model. The dates shown in the movie place it in 1960-1961.
In the opening sequence taking place in 1959, a one dollar "Green Seal" Federal Reserve bill is shown. The treasury dept introduced them starting in 1963. "Blue Seal" Silver Certificates were in use in 1959.
When the "payola money" is exchanged, "Green Seal" Federal Reserve Notes are again seen.