When Maurey and Sam first try sex, Maurey, in the long shots, is wearing panties with dots on them. In the close-up when she takes them off, they are plain white.
Maury says that if Sam has to go to military school, in 4 years he will be 18 and can do whatever he wants. But the age of legal majority was 21 in 1963, and wasn't lowered to 18 until 1971.