In the first scene in the van when they're driving to Bad Rock, Hannibal takes BA's blood pressure and checks his watch. A minute later Hannibal checks his watch again except the watch isn't there. George Peppard nonchalantly goes on with the scene.
The doctor said she needed AB negative blood for B.A. He does not need to receive blood only from someone who's blood type is AB negative. He can receive from A negative, B negative, O negative or of course AB negative. Approximately 16% of the population has one of the negative blood types.
In the early 1980's a small town Police department would not have been able to run the fingerprints of Face and Hannibal so quickly. It would have needed to be done manually and cross checked which would have taken hours or days.
The paper used to make the pseudo-dead-end in the alley is clearly not toilet paper. It's obvious when Face is stapling it to the pole. It is obvious because it isn't toilet paper its a large roll of commercial paper towels most often used in a paper towel dispenser in public restrooms and commercial offices.
In the early scenes, the team arrive at the doctors house and knock on a green door. When the doctor opens the door it is blue, as is the woodwork inside the house. This is incorrect. The interior woodwork is a cornflower blue, however the exterior woodwork in both scenes is a lichen green as evidenced by the edge of the opened door being cornflower blue and the front street facing door is still lichen green.
At 14:50 the motorcycle dudes cut down the telephone pole outside of town. But at 16:00, the local sheriff is hanging up the phone from a call to the town's doctor.
Face refers to Vietnamese currency as "yen", when it is actually known as "dong". Yen is the Japanese currency.
When Dr. Sullivan dials the sheriff, the first digit she dials is '1'. This would be for a long distance call. She only dials seven digits for a local call.
Throughout the motorcycle gang is called the Barbarians until, without context, Hannibal calls them Grizzlies.