In the Indian park, when Grace displays her collection of pistols, they change their layout between cuts - a revolver disappears and the flintlock pistols are moved down to take its place.
At about the 16-minute mark the sidekick character of the slave traders, New Mark, tries for several seconds to get his gun out of its holster. It a motion that he should be very adept at instead of fumbling at it as though it's stuck in there.