When Cal marks the due date of the baby on the 20th and 21st, a February calendar is shown with 28 days. The real kidnapping happened on February 19, 1988. February 1st was on a Monday in 1988 and it was a leap year with the 29th also on a Monday. So, this calendar is not correct for 1988, however, it is also not correct for 1992, the year this movie was released.