When Banner gets back to his cabin, he removes his right boot to reveal a blood-soaked foot inside. The camera cuts to his wife asking him what happened, and then the camera cuts back to him. Now, the boot is removed his left foot. There wasn't enough time to remove both boots.
The roof of the truck is neither strong enough to roll the truck when pushed sideways; nor is it strong enough to support the truck's weight when upside down. Early vehicle roofs were barely more than umbrellas. They were not required to support the vehicle's weight until 1975 (for US-sold vehicles).
Spencer uses a break-action, two-barreled weapon, but when in the tree with lions and hyenas attacking he fires three shots, multiple times, between reloading.
In the gunfight between the cattlemen and the Banner's shepherds John and Jacob are using lever action rifles, but at no time are they seen being cycled, only fired.
When paying for the drinks in the speakeasy, small (current) sized bills were used. Bills were much larger prior to 1929. In 1929 they reduced the size of US currency by 30%.