Goofs

When Old Matt goes into the house at Moaning Meadow and opens the window, there are papers (probably sheet music) on the piano. When the camera angle changes, the papers are gone.

Sammy walks barefoot through mud and water to get to the general store. When she enters, her feet are dirty, but she leaves no wet footprints on the floor. Shortly after, she arrives at a farmhouse with completely clean feet.

At the end of the fight between Young Matt and Wash Gibbs when Sammy leans down to check on Matt, she is clearly wearing a fur-lined moccasin, but immediately before and after, she is barefooted.

When Matt opens the door to Daniel, who is calling on his family to make a down payment on the land (around 65 minutes), the door has three large vertical wooden panels. A moment later, huge vertical chunks are missing with a different framework only to reappear just as suddenly.

Just prior to Daniel (Harry Carey) shooting Matt (John Wayne) Sammy (Betty Field) is seen in a blue dress and runs to try and prevent the shooting. She's next seen after the doctor's operated on Matt but wearing a grey dress with a red top underneath.

When Old Matt opens the house in Moanin' Meadow, it had apparently been closed up for years. Yet there was little dust raised when he opened the window. And the piano was exactly on key. Anyone who deals with piano tuning and maintenance can tell you that the nasty temperature and humidity changes to which it would have been subjected would have wreaked havoc on the tuning.

With both shootings later in the film there is absolutely no trace of blood. This is particularly surprising in the first case which is at point-blank range.