The bait shop where Stig stores his weapons and he and Bobby meet up after escaping NAS Corpus Christi is obviously not in Texas. It is against Texas Alcoholic Beverage Commission law to have neon beer signs on exterior windows.
When Bobby and Stig are arguing over who is going to kidnap Papi, Stig drops the key's to Papi's truck on the ground. The keys he drops shown in the shot on the ground are to a Chevrolet , however Papi's truck is a Dodge Ram but this does not stop Stig from from using them to drive away in the truck.
When Bobby and Stig cross into Texas from Mexico, they walk through the Rio Grande which flows from their right to their left. But the Rio Grande flows east along that border, so it should be left to right when they walk north. As depicted, they're going the wrong way.
When Stig is lying to the border guard he says that his aunt in Tuba City had a heart attack and later mentions that Tuba City is near Odessa. Tuba City is in Arizona. The nearest town named Odessa is in Texas, which is more than 700 miles away.
Both men (Stig and Bobby) take a beating with a bat to their ribs. The next day they are both walking and moving around like nothing has happened. They would have multiple broken ribs at the minimum; lung contusions and/or collapsed lungs are also likely. But they definitely wouldn't walking without significant pain and possibly difficulty breathing. No amount of conditioning would protect the ribs in a situation like this.
While wearing the Navy Lieutenant Commander summer whites uniform, Bobby is wearing black shoes rather than the required white shoes. In addition, his beard is out of Navy regulations, unless of course, he had a "no shave" chit.
At one point in the movie, both main characters are on a Navy base in Corpus Christi, Texas - the Navy actually does have an air base there. A building explodes, and the flags burning on the pole outside are the POW / MIA flag, and the US Marine Corps flag. The Marines do not have a base anywhere in Texas, and their flag would not be displayed on a Navy base.
Bobby tells Stig that his sniper rifle is a military version even though Bobby is across the street, at night and with Stig partially hidden behind a roof ridge. Bobby could not possibly tell what version of rifle Stig has under these conditions.