What does the first box signify, 264?

 

I have two broadcast cards from cars I've owned or currently own. The label on that box is "SEQ," so I'm guessing "sequence" number. But it's only a 3-digit number, so there can't be more than 1000 values for that box (000 to 999). Which means that it's not likely to be a number unique to the car. Maybe it was the order of the vehicle as it went down the assembly line that day or that shift?

 

Thank you, just curious as I saw a pic of a broadcast card on this site for another 70 442 w car and it had the same numerals in that box.