In the scenes on crossing the Rio Grande you can clearly see the water flowing from left to right looking from Texas to Mexico. The river, of course, flowing from west to east all along the Texan/Mexican border should be seen flowing from right to left.
In the camera shots between Lincoln Rogers Dunnison meeting George Durham and arriving in Brownsville, Lincoln's facial hair changes as his sideburns get thinner and change shape.
The film is supposed to take place along the Nueces Strip, the coastal line from Nueces County to Brownsville. However, the film frequently shows hills and mountains, which are not found within 200 miles of the Nueces Strip.