In the final battle, Gibson's character is shown advancing on the Dragoon leader with a pistol in his right hand, he's holding the pistol by the barrell, using it essentially as a club. We can clearly see that he does NOT have any other pistols in his belt. He realizes the American line is breaking so turns to rally the troops. As the camera changes to another angle, Gibson is seen still holding the pistol in his right hand, but he is suddenly now holding it by the handle!

Once he grabs the American flag and charges forward, we clearly see him throwing the pistol off to his right...it's quite obvious & he throws it high & far, not just a quick drop. Once again the camera angle changes and suddenly he has a pistol in the front of his belt! This pistol sure does get around.