Deliberate mistake: At the beginning of the movie Mr. Coates tells his wife that he will be gone "all of three months, maybe four." The first time we see Bud and Elizabeth Searcy she tells Travis that her dog is pregnant and that Old Yeller is the father. We then see her dog that does not look very pregnant. The next time we see Elizabeth she presents Travis with one of the pups. The problem is that the pup that was supposedly just born is about 4 months old.
Plot hole: Towards the end of the film when Newman and the remaining stagecoach people are in the cabin at the top of the hill, Richard Boone's character sends one of his two henchman (the Anglo, not the Mexican) around to the back of the cabin to apparently surprise them from behind. Then Newman's character walks down the hill and Boone and the Mexican henchman are all killed in a shootout. Everyone comes out of the cabin, comes down the hill and the credits roll. I guess that now, almost 40 years later, that poor Anglo-henchman is still behind the cabin, waiting for them to come out.
Continuity mistake: When Levoi and Crowhorse visit Grandpa for the first time note the white and black beaded belt on the table behind Grandpa. In the beginning it hangs at the edge just at the first black stripe. Just after Grandpa trades Levoi for his glasses and hands him the rock, the belt now hangs nearly to the second black stripe. After that cut the belt now hangs in its original position. (00:37:30 - 00:38:30)OneHappyHusky
Deliberate mistake: When Raza is chasing the "empty" train, as it goes over the trestle just before he stops it, you can see the engineer in the train's engine.
Revealing mistake: During the shoot out with McGivens's gang at the Cortez ranch, the wife of Cortez sneaks out of the trap door with her baby and peers around the side of the building. You can notice that the baby is really a doll.
Continuity mistake: In the trailer, there is a scene showing Matt Damon in a fight. The other person pulls out a knife and cuts Damon on the right side of his face, leaving a big scar. In the next scene of the same commercial the scar changes from the right side of his face to the left side and then back again.
Factual error: Somewhat late in this German made western, Lex Barker and company are led into an Indian village, somewhere in (I presume) the Rocky Mountains. You will notice that there are at least two totem poles in this village. The kind of Indians shown dress like Plains Indians, and not like Northwest Indians. Northwest tribes who are found in Washington state, USA, and British Columbia, Canada, are the only tribes with totem poles. Plains Indians did not have totem poles.
Continuity mistake: Sacajawea (Donna Reed) dives into the water to retrieve some important maps, which have fallen in and been taken to the back of the boat. When she dives in, the maps are back to the original area they fell into, when they should have been quite a distance from where they landed in the water.keiko
Factual error: While the Confederate captain is explaining the mission, a couple of the "patriots" are inserting cartridges into their Colt Peacemakers. A neat trick, since the Civil War ended in 1865, and the Peacemaker wasn't introduced until 1873.
Visible crew/equipment: In several scenes there are rectangular arrays of studio lamps visible, reflected in the actors' space helmets.
Other mistake: Throughout most of the film, Mattie Ross' gun is correctly shown to be a Colt's Dragoon .44 caliber revolver. However, in the scene where Tom Chaney is looking down at her from the top of the well into which she had fallen, the gun in his hand is a Colt's Model 1860 Army. Presumably, when he, too falls into the well after being shot by Marshall Cogburn, the gun goes with him. When Cogburn retrieves the weapon before helping Mattie out of the pit, the gun is once more a Colt's Dragoon.
Audio problem: When Bunny (Ramon) is, as Zorro, spelling out "Zorro" on the wall with his whip, the number of whiplash sounds does not match the number of marks in the wall.