It's there, it's just small and hard to see.
I acquire all the serial numbers off new equipment the day i receive it and put them into my equipment database for records keeping. I also photograph the item, and the receipt. I keep that record with my insurance policy.
I've had to use a camera to get the serial number from various bits of equipment that have it in ridiculous and difficult to see location ... like my desktop computer. It's great to have it recorded in the database as then when some idjut customer service person on the phone insists that I supply it before asking a simple question that has nothing to do with the computer itself, I can just read it to them without acting like a contortionist to find it while on the phone.