Goofs

When Rio bluffs Deputy Lon Dedrick into opening his jail cell with the unloaded derringer, he takes Lon's six-gun and cocks it. Moments later, he needlessly cocks it a second time.

After 5 years in a 19th-century Mexican jail, Rio looks like the food there was Cordon Bleu. Not only does he not look worse for wear, but he even looks a little better than before he was incarcerated. An actual prisoner likely would have lost 30 pounds.

When Rio inspects the two-barrel derringer smuggled into the jail by Luisa, both barrels can be seen to be unobstructed throughout their entire length. However, when Rio is later pointing the derringer at Lon, it can be seen that muzzle end of the lower barrel is enclosed by an end cap, allowing only the upper barrel to fire if he'd had ammunition.

When Lon discovers the derringer concealed in the soup bowl outside Rio's jail cell, Louisa shows Rio the two cartridges she has in her left hand. She then rushes the cell and puts both her hands around Rio's neck, but both hands are empty, and there are no cartridges dropped on the floor by the cell bars for Rio to pick up after Lon leaves with Louisa.

In the market, Rio barters with a market girl over the price of her necklace. He first offers her 20 dollars, which she does not accept. When he ups the offer to 30 dollars, she agrees, taking off the necklace and giving it to him. Later, Rio gives the necklace to Luisa, telling her that he received it from his dying mother. When he eventually confesses to Luisa that he bought the necklace from a woman, he claims that he paid 25 dollars for it.

In the final shootout, Sheriff Longworth has a six-shooter, but shoots off eight bullets without reloading.

In the La Playa Bar shootout, the drunk Howard, on his knees, fires his shotgun at a downward angle, and knocks out the window above.

During the fiesta in Monterey, a California state flag can be seen. The scene is set during 1885, but the flag on display is the modern version, standardized in 1953.

(at around 56 mins) The glass tankards that the party-goers drink from in the fiesta are of a design first produced around the 1920s.

In the early segments, when Rio is wearing the sugarloaf sombrero, there are two metal grommets for ventilation visible on the upper left side of the hat. This is not likely for a hat made in rural Mexico in 1880.

When Lon returns to the jail cell after Rio succeeds in acquiring the derringer brought there by Louisa, there is the sound of the derringer being cocked by Rio, yet the hammer remains in an uncocked position.

During his attempt to seduce the young Margarita, Rio keeps referring to her as Señora. Señoras are married women. He should've referred to her as Señorita.