John Wayne had a few SA's that he used in films, but the one that's most recognizable is the one carried in his later years, which were supposedly fitted with ivory grips. What most people don't know is that his Colt SAA started out in 1909 as a Bisley Model that an unknown individual converted to a SAA.
In October 2007 an article appeared in the American Rifleman written by Gary Johnston that does an excellent job describing this gun. The barrel is still Bisley marked and the grips are faux ivory with finger groves carved into the inside panel. Apparently Wayne aged them by placing them in water that contained tea. The caliber was originally 44-40, but had been converted to .45LC in order to handle the 5 in 1 movie blanks.
I spoke to the author last year, cause I also have a converted Bisley that experts believe was done at the factory, but it also has on numerous parts of the gun matching 3 digit numbers which was a practice of Colt to prevent parts being mixed up with other guns. This proves you can't believe what you see in the movies and the Duke couldn't be trusted to have real ivories, but then again who gives a damn?
This is my Bisley 32-20 mfg 1906 and trigger guard and back strap mfg 1904. Mine also has Bisley on the barrel.