well mine came loose with Henry if that helps, where is the serial number on them normaly? maybe im not looking in the right place
I couldn't find the serial number anywhere on the system either. I got mine from the box, so if you don't have a box, it looks like you can't tell.
If you have the manual, it's on there too.
On a side note, I notice in the battery compartment there is a sticker that says PA2317 and on the box's UPC label there is a similar sticker that says PA2327. Anyone know what those mean? Is it like a "this is the 2,317th system made and the 2,237th box made"? Or are those the serial/part/model numbers?