Well, I discovered what the black writing on the bottom of my Skylanders are. They're production numbers, and I want to know how to tell what batch of a Skylander I have. I'm going to share a few of the production numbers on the Skylanders I have so you can help me here: (i'll update this when I get more 'landers)
3DS SSA Starter Pack



: S1123
PS3 SG Starter Pack



:L3126
Replacement

from Activision:S3117
LC

:L4125A
S2

:E4126
S2

:
E4125 (is with blue crystals)
S2

:
E5120

: E4129 (with an "A" below the "Made In China" text
S2

,

and Dragonfire Cannon: E3128 (cannon has an "A" to the right of the production number.)
I need to know what they mean. Does a bigger number=later batch? What are the letters for? I want to know.
UPDATE-5/23/2013: changed the title a little bit. I was thinking of starting a new thread dedicated to production numbers though. Is this one sufficient enough not to start a new one?