Into the show about 10 minutes the stagecoach overturns and while the cast is getting out, the wheels are still spinning. As they slow down you can notice they are spinning in opposite directions. That's not something that can happen.
Towards the end, Maverick is in jail and while the deputy sheriff is away he sees a set of keys next to a ledger and a pen on the desk. He ropes in the keys into the cell, but finds out those keys don't open the door. Hearing the deputy sheriff coming back, Maverick quickly throws the keys back onto the desk next to the ledger, but there in no pen in sight.