Continuity mistake: The boot heel West removes to obtain his hidden explosive somehow reattaches itself by the time he leaps into the mining car. (He doesn't stop to put it back - he's running for his life from a pack of hungry wolves.) His boots also change from black to brown by the time he makes it outside and jumps on his trusty horse.
Revealing mistake: Though the stock footage is of a real wolf, the animal West wrestles with is too-obviously a dog wearing a fake pair of wolf ears. In later wrestling matches between West and the wolves, the attacking beast is a stuffed prop that never moves its legs, head or jaws at all.