Although the film's fictional namesake has scenes filmed in the Copacabana club in New York, the club was not open until November 1940. This is not consistent with the actual film, which is set during the Great Depression.
When Cecelia is playing the ukulele in the music store she is strumming along to the song and the song stops. She continues to strum along after the song is over, but there is no sound. The ukulele playing was obviously dubbed in.
Although the film is set in 1935, the "inner" film has no specific date so the reference to the Copacobana Club, which opened in 1940, could simply be forward thinking by the director of the inner film. Also Tom remarks in New York that 24 hours previously he was in Egypt. It would be many years after 1935 that he could have done that journey so quickly by air.