When Deputy Gibbs (Morgan Woodward) talks about a stock split going three for one on a railroad stock that Doc Holliday (Douglas Fowley) bought, he says that Doc tripled his money. Actually, a stock split of three for one would reduce and adjust the actual price of the additional shares so that the net outcome would leave the owner with the same monetary value as before the split.
The safe crackers use plastic explosives. Plastic explosives weren't formulated until 1875 in Europe by Alfred Noble. It wouldn't be widely available until World War One.