Some cars have 4-digit date codes on the base. These date codes are more specific than the 3-digit codes as they indicate the day a car was made instead of just the week. For the 4-digit codes, the first 3 digits indicate the day of the year and the last digit is the year. A date code of 1987 would indicate the car was made on the 198th day of 2017 (July 17). A code of 0250 would be the 25th day of 2010 (or 2020; depending on the car).