Although the setting of the park is, ostensibly, the Old West at least two firearms with no place in it appear in the episode. On the back of the wagon that drops off The Man In Black and Lawrence at the prison there seems to be an M1917 Browning machine gun mounted. That weapon was not introduced until, literally, 1917 well after the 'Wild West'. In addition Logan appears to pick up either a Smith&Wesson Model 10 or M1917 revolver as an 'upgrade'. Either model was not available until shortly before or after the twentieth century. However, as this is constructed world and not retelling of a real one, creators of the park could prefer to have some guns from later periods.
During the raid on the town, Hector is using an 1873 Winchester rifle, which is a lever action. When he fires the second shot into the deputy on the ground, a close up shows a cartridge case being ejected from the rifle. This is not possible, as the case isn't ejected until the lever is manually operated, which can be seen in the next shot of Hector.