Jerry types an address on an envelope, but when she seals a letter inside it, the envelope is still blank.
The beginning of the movie is 1925 shortly before Jerry's marriage, yet, "Singing in the Rain" is playing on the radio.
The song was composed for Hollywood Music Box Revue in 1927 and really popularized in MGM's Hollywood Revue of 1929.
1928 was Jerry's 3rd Wedding Anniversary, yet, the band in the nightclub/speakeasy is playing "Happy Days are Here Again" which was not composed for another year.
