It’s most likely just something done to help with the manufacturing process.
I’m assuming it’s a way to track which machine/die/die-section was used to punch out the blank. If there is an error on some of the blanks, they know where to look to find the problem. That’s just a guess, but I’m sure it’s something like that.
I had also wondered about those numbers. I had initially thought it could be related to the title it was included with, but I have since disproved that.