John Wayne could not sing. The songs were dubbed by Bill Bradbury, a son of director Robert N. Bradbury.
The pre-recorded songs that John Wayne is pantomiming to as Singing Sandy have, in reality, a four-string ukulele instrument accompanying - not a six-string guitar. Furthermore, the rapid strumming technique is indicative of Hawaiian music that reached its zenith of popularity in the 20s, and might be viewed as something of an anomaly compared to the many cowboy songs that would emerge within a few years of this movie's date.
Marlon Brando's line from O Poderoso Chefão (1972) "I'm going to make him an offer he can't refuse" was not an original term, as may be believed by some fans of the movie. In 'Riders of Destiny', Kincaid made a similar devious statement (see the Quotes section) nearly four decades before O Poderoso Chefão (1972) was released.
The failure of the original copyright holder to renew the film's copyright resulted in it falling into public domain, meaning that virtually anyone could duplicate and sell a VHS/DVD copy of the film. Therefore, many of the versions of this film available on the market are either severely (and usually badly) edited and/or of extremely poor quality, having been duped from second- or third-generation (or more) copies of the film.
The earliest documented telecasts of this film took place in Detroit Saturday 9 April 1949 on WXYZ (Channel 7), in FOrt Worth Monday 2 May 1949 on WBAP (Channel 5), in Cincinnati Thursday 28 July 1949 on WCPO (Channel 7), in Atlanta Friday 9 September 1949 on WSB (Channel 8), in Los Angeles in mid-1949 on KTSL (Channel 2) and Saturday 25 March 1950 on KECA (Channel 7), in Philadelphia Monday 6 February 1950 on WFIL (Channel 6) and in New York City Monday 18 September 1950 on WOR (Channel 9).