Other mistake: When Bowie and his men first enter the Alamo, Travis calls for the colors ceremony and the detail marches to the flagpole. One section is ordered to "halt", then the order "about face" is given. However, the detail does a "right face" instead.
Other mistake: When encased in rock, George lights a match to see the current time dial on his machine. But the dial is backlit every other time its shown.
Other mistake: When the character plays the guitar throughout the movie, there are obviously no strings attached to the guitar.