I noticed the serial number sticker on the top of my sega mini 2 box, and found a few more on ebay, if you don't mind share your number in this post.
12U032981
12U049077
12U069800
with other sega products, the 1st number was the factory at which the console was assembled. It is represented by one number, one letter, or two letters. followed by the year that the console was assembled. This is represented by the last digit of the manufacturing year (EX: "3" = 1993, "4" = 1994, etc...). production run indicator, which is represented by one letter or one number. number units produced during the production run up to the one in your possession. A single production run could consist of no more than 999,999 units.