The tombstone for Gordo states his title/rank as CPT U.S. Navy. In the Navy, the rank of Captain is abbreviated CAPT. The abbreviation CPT is used by the Army, and the abbreviation Capt is used by the Air Force and Marine Corps.
(Spoilers) Tracy Stevens' headstone shows her to be a Medal of Honor recipient. However, since 1917, the Medal has only been awarded to military service members. Tracy never served in the military. Service in NASA does not qualify, as it is a civilian agency. A better alternative would have been the Presidential Medal of Freedom, for which she would be eligible.
The stock footage of Ronald Reagan shaking the hand of "premier Andropov" shows Mikhail Gorbachev. Gorbachev did not become leader of the Soviet Union until 1985.
The funeral coach shown at Gordo and Tracy's funeral (at 01:05:35) is a 2000 Cadillac DeVille--a car that doesn't exist for 17 years.