i think its a number indicating batch, and country. I have two LODs both from different batches, easy to tell cos of the LED, etc, they have different numbers
MY friend has a T1 he bought in singapore. it had SGXXXXXXX on it. My T1 came from fenix-store and it has USXXXXXX on it. When i was in hongkong, the fenix lights had CNXXXXXX on it.
Crenshaw