How do I extract the Serial Number from a Linux-based appliance?

[dirovame]

I've scourged the internet for weeks now in search of a way to gather the serial number from a number of single-use Linux appliances (Ubuntu 14) that will only spit out the below value:

Serial Number: To Be Filled By O.E.M.

Is there anywhere else the serial number might be stored? I've checked BIOS and was not able to find it.

Thanks

 

[Snipergod87]

Off the motherboard?
If it is not filled by the OEM (Esp if it is not an OEM system) than it won't be there.