In some driving scenes, the lines in the streets are yellow. Also some warning signs are in yellow, and placed higher on their respective poles. This is not correct for the 1940s. Lines were white. And signs were placed closer to street level for ease of viewing.
Harry attempts to call home from a Restaurant; instead of getting a connection or a busy signal, he get's an "out-of-order" chirp. He dials "O" and tells the Operator that his home phone is O.O.O., he gives her a five digit number, then looks in the phone book and finds his next-door neighbor who of course has the traditional "Waddington 1234" number" used in 1949.