In a 1988 interview Gloria Stuart claimed that the only direction John Ford gave her was to cry louder when her doctor husband was condemned.
On the envelope Buck hands to Mudd in prison, the prop department took the time and effort to get the correct 1861 Washington three-cent stamp and the spiral cancellation mark as well.
The $50 Dr. Mudd gets for setting Booth's leg would equate to about $770 in 2017.
John Carradine originally auditioned for the role of Abraham Lincoln, which he later played in Of Human Hearts (1938).