The codes on the stickers on 2" Quadruplex tape spools
 

I have a pair of Scotch 2" Quadruplex reels. I was curious about the stickers on the back.

http://www.matthewkurth.com/content/mmc_quad.jpg
http://www.matthewkurth.com/content/blank_quad.jpg

Clearly the bottom sticker tells us the tape type and length, but do the top stickers tell us anything useful? Presumably it's lot and line numbers but I wondered if it might indicate when the spool was originally loaded with tape (since there's no real guarantee the spool hasn't been reused).