The nurse giving Olivia medication in the opening and closing scenes addresses her as "Mrs. Anderson" even though her name is "Olivia Hutton" and the card in the medication tray also states "O. Hutton".
The movie takes place in 1951. Towards the beginning of the film, just after young Greenberg's funeral, a group of school friends are seen with a large, black sedan in the background. It's a 1955 Cadillac.
Olivia makes reference to a quote attributed to Benjamin Franklin when she says "Democracy is two wolves and a lamb voting on what to have for lunch." Franklin most likely never said this. This quote does not appear in any of Franklin's writings and the word "lunch" did not enter the English vernacular until the 1820s; decades after his death.