I'm trying to find the manufacture date of my Droid Razr and DROID RAZR HD

[Droidlynn]

Hi there,
I am curious as to how I can find the manufactuer date on the Droid Razr and Razr HD. I heard theres a way to find it but havent been able to figure out how. I like to know how old my Droids really are, out of curiosity. Thnx,
Droid