When starting his TV address, Ted's tie knot is skewed to Ted's left and it then centers itself in later shots.
The movie depicts the moon being full on the night of Kennedy's crash; in reality, the moon was full July 29, which meant that it would have been a waxing crescent on the night July 18.
The car Ted Kennedy was driving at Chappaquiddick was a 4 door sedan with center pillars behind the front doors. The car in the movie is a 4 door pillarless hardtop. .
Ted asks the operator to make a collect call and gives his name, but never gives a phone number. The operator patches the call without it. By the late 1960s, pay phones allowed callers to directly dial a collect call by dialing a 0 rather than a 1 before the area code and phone number, and then telling the operator who picked up that it was a collect call and giving the operator his/her name.
When flying the kite at the beach, the kite is shown flying out over the water, but the wind is blowing onto the shore as evidenced by the way the grass is bending.
When Mary Jo's body is going by and Ted Kennedy is on the payphone there's a sign above it that says, New England Telephone. A Nynex Company. It was the Bell System back then. Nynex became a company in 1984 with divestiture.
In the scenes at the Inn when they use a payphone the phone is a newer type that the Bell System introduced in the 70's to combat vandalism. Also the hole on the side of the phone should show a lock that differed in the state it was in to open the top part.
One of Kennedy's advisers uses the term "as pure as Mother Teresa." Although the BBC aired a documentary in the UK on Mother Teresa in 1969, it was not until 1971 that the US knew of her work through the book, " Something Beautiful for God."
The exterior door used in the movie as the home of the Kopechnes is a fiberglass model with an oval glass insert with brass caming. This style of door didn't exist until the mid 1980s.