During the 1962 party at Jack's house, his mother is reading the book 'Catch-22', a book first published in 1961. However, the copy she is reading is an edition that had not yet been printed. The photo of author Joseph Heller on the back of the jacket is clearly from years later than 1962.
(at around 40 mins) Matt throws his raggy cloth at the oncoming car's windscreen. It misses and hits the top of the car's side window. In the next shot, the cloth is firmly across the whole bottom half of the car's front windscreen.