When Mark loads the tyre into the trunk of his car and starts driving off to John du Pont's residence; as soon as he cuts into the road, there is a White Toyota Camry XV20 (1997-2001) parked in front of his building.
At the hotel after the US trials in Pensacola, David knocks on John DuPont's assistant's hotel door which has a key card lock. Keycards were invented in 1979, but were not in widespread use until the early 2000s. It might be possible, but unlikely used in a cheap motel where the wrestlers stayed.
When the nurse wheels in DuPont's mother to watch the wrestlers training, the nurse has a stethoscope around her neck. Subsequent shots show the nurse without the stethoscope. The stethoscope appears and disappears between successive shots.
During the Olympics trial in 1988 at Seoul, Mark gets defeated at the first attempt. Dejected, he returns to his room and bangs his head against the mirror in frustration. There is a big cut on his forehead. But when he returns again for the final round, there is no scar on his forehead.
Towards the end of the movie, Mark is shown entering the UFC cage to compete. He is shown going up against a white MMA fighter when in reality, Mark Schultz fought Afro American MMA star "Big Daddy" Gary Goodridge.
When Mark is trying to make weight after his eating binge he is seen naked on the scale with a towel draped over his shoulders. If he had shed his clothes for the weigh in he would not have had a towel on as every ounce counts.
When the Army delivers the armored personnel carrier to DuPont it is identified as an M113. This is incorrect. It is a T113 or T117, the prototype trial versions. Visually the prototypes were virtually identical to one another, with the biggest difference being that the T113 was mainly aluminum and the T117 was steel. Largest visual identifiers from the movie between the prototype (T113) and production version (M113) are as follows:
1- Vertical glacis plate on prototype is sloped on production version.
2- Track return rollers were not present on production version.
Early in the film the school secretary writes a check to Mark for $20 and dates it March 1987. Later, du Pont writes a check to Mark for $10,000 and dates it May 1987, indicating that two months have passed. But the exterior shots in between these two scenes show trees with the brilliant colors of autumn.