Of Fox's 8 MOTOs, this was the sixth to be produced, and the seventh to be released. Copyright 1938, not released until January 1939.
The program outside the Sultana Theatre includes Charlie Chan in Honolulu, with a "Last Day" notice pasted over it - a tribute by the cast and crew of this film to "Chan" star (and fellow 20th Century Fox player) Warner Oland, who passed away in his native Sweden while this film was in production in August, 1938.
The reason this film is shown more often than any of the others is because it's in the public domain, and no longer under the legal control of 20th Century-Fox.