When Byron shows up for Dexter's wedding, Dexter makes the comment that the bride is ready for the "Rumble In The Jungle". This wedding scene is happening in late 1972 or early 1973. The "Rumble In The Jungle" (boxing match between Ali & Foreman which spawned the expression) was October 30, 1974. No way he would've used this expression at the time of the wedding.
The World Trade Center towers were not complete until 1972, but they are shown occupied and on postcards in the fall of 1970.
Eileen and Byron move to New York City after the Kent State shooting in May of 1970. They show the U.S. Postal strike when they are in NYC. The postal strike occurred in March of 1970.
Byron gets caught up in the Hard Hat Riot. The Hard Hat Riot occurred on May 8, 1970 (4 days after Kent State.) However, the movie shows it happening well after that.
The recording session of "Dancing In The Moonlight" is incorrect. The scene is shown happening some time after Nixon's re-election in November of 1972. However, the song was released by King Harvest in July 1972 and had already been a hit by this point.