Robert tells Gloria about a film he saw starring Anita Louise and Richard Cromwell in which Anita Louise's character has a brain tumor. However, Louise and Cromwell only made two films together, Most Precious Thing in Life and The Villain Still Pursued Her. The depression-era dance marathon, which is the subject of the film, presumably takes place in 1932. Earlier in the movie, we hear Mrs. Layton tell Robert and Gloria that they are her favorite couple because they are number 67, the same year that she was born (1867). Shortly thereafter, Gloria tells Robert that she's figured out Mrs. Layton is 65-years-old. Sixty-five years after 1867 is 1932, which is prior to either of the Louise/Cromwell films.
When Gloria's partner is rejected from participating in the marathon for being sick, she points to Ruby and snaps, "If she ain't pregnant, I'm Nelson Eddy." In 1932 Eddy was not yet a well-known figure in show business.
The Edward Heyman/Johnny Green song "Easy Come Easy Go", which is used as the film's title theme and is performed by a singer at the fictional dance marathon, was not published until 1934 (two years after the film's 1932 setting).