The first two films were made with RKO, while Rio Grande was made with Republic Pictures. John Ford, John Wayne and Maureen O'Hara were originally supposed to have made The Quiet Man first, but Republic, one of the smaller studios, wasn't certain about the prospects for The Quiet Man and insisted that Rio Grande be made first to cover any potential losses. (Ironically, The Quiet Man would go on to make more money than Rio Grande.) With Republic, the budget for Rio Grande was roughly half of what was spent on Fort Apache, and indeed some of the more manpower intensive scenes in Rio Grande were recycled from Fort Apache.
This would be the first of five films that paired John Wayne and Maureen O'Hara. John Wayne's son Patrick Wayne makes his film debut, but not as LTC Kirby Yorke's son, but as an uncredited boy. (Although many might assume that LTC Kirby Yorke is just an older version of CPT Kirby York from Fort Apache, this is not the case. Victor McLaglen and Ben Johnson play characters who had similar names in She Wore a Yellow Ribbon, but they are obviously different characters as well.)
Cavalry troopers carry Colt Single Action Army revolvers as sidearms. There appears to be a mix of both Quick-Draw and Cavalry models.
Winchester Model 1892
Many of the Apaches are armed with Winchester Model 1892 repeating rifles. Troopers Boone, Tyree and Yorke are armed with them when they sneak into the Indian village.
Winchester Model 1873
Some of the Apaches are seen with Winchester Model 1873 repeating rifles. Much of the footage of the Apaches firing is reused from Fort Apache.
Winchester Model 1876
Some of the Apaches are seen with Winchester Model 1876 musket carbines. Much of the footage of the Apaches firing is reused from Fort Apache.