How to find the date when your thunderbolt was built

[anon(14828)]

I am trying to find out how to find the date when the tb was built. I know there was threads about this already but cant find them. I am just about to buy 2 from best buy. they have a green sticker lol

 

[bthomp21]

thought someone said under the case where battery is, but not too sure.

 

[FutureTBoltOwner]

its on the inside of the battery cover door (the part that physically comes off the phone to get to the battery) look at the top right corner is where they're generally located