What is the signifigance of 10-2-and 4 in the Tim Mcgraw song Back when?

Answer 1

maybe a reference to Dr. Pepper soda, back in the day it said 10-2-4 on the bottle. It was a holdover from an earlier campaign to "Drink a bite to eat at 10, 2, and 4 o'clock"

Answer 2

Yes, the Dr Pepper reference. It was said back in the day that polls had proven that people were the thirstiest at 10, 2 and 4 o'clock. Weird huh? Dr Pepper capitolized on that in and incorporated it into their logo