At the dinner table in Maryland, Jordan Benedict states that his ranch is 595,000 acres. Later on Leslie refers to Reata as being 500,000 square miles. An acre equals 1/640th of a square mile. The state of Texas is only 267,339 square miles, so Leslie was saying that the ranch was almost twice as big as the entire state.
The newspaper shown announcing Angel Obregon's return has an article about Alfred Chester Beatty giving up his American "nationality" and becoming a British citizen. Beatty was a real person that did this in 1933. The newspaper shown is from that year when it should have been from sometime between 1941 and 1945.
When Jett is talking to the Oil executives about "cracking Benedict", he is seen from behind with a cigarette in his mouth, but then is seen shortly after from the front with the cigarette in his hand.
In the Jett Rink Airport opening day parade, there are riders on horseback carrying an American flag, and a Texas flag. The American flag being carried has 37 stars (should have been 48), and the lone star on the Texas flag is upside down (the stripes are right side up).
The large display of flags in the lobby of the home has the American flag in the wrong position. It is on the right, as we see it. However, protocol requires Old Glory is to be presented "on the flag's own right," (aka stage right) meaning our left.
The newspaper announcing Angel Obregon' homecoming has an article headlined "Full-Paid Taxes Record Broken". The text of the article refers to Los Angeles County and Howard L. Byram. By ram was the County Tax Collector for Los Angeles County in California. Its unlikely a story like this about L.A. Would be in a Texas newspaper. It appears that the production used a real California newspaper and added the picture of Angel.
During the confrontation between Bick and Jett in the hotel banquet hall stockroom, Bick throws a "basket" knocking over several storage shelves. The shelves start to fall before the basket actually makes contact.
In the scene where Leslie faints at the barbecue, long shots show Luz standing at a table with no one behind her. But in the close-up after Leslie faints, when Luz says, "That's what I was afraid of", there is a crowd of people in the background behind her.
When Jordan forces his son to ride his horse with him at a gallop, the child dummy is clearly slipping down out of the rider's grip as he comes to a stop. The immediate close-up has the child actor sitting perfectly erect.
When Jordy introduces his new wife Juana at the pool party, the people behind Bick and Leslie are seen applauding, even though Jordan hasn't finished his announcement yet. Also, no sound of clapping is heard.
The oil wells seen in the backgrounds of live-action shots, such as at the railroad depot, are clearly miniatures erected in the near background in an effort to give the impression of size through forced perspective. Similarly, the wells seen through the windows of indoor sets (the house and the diner, for example) are plainly painted images on false backdrops.