You need to get the serial number, for a license/TAC case etc, and its stuck in the rack, 3000 miles away.....
There are 2 ways to get this, from the GUI, and from the CLI.
From the CLI - If you SSH into the MARS box, and run a SHOW INVENTORY, you get the model number, whether its a local or global controller, plus the Serial Number.
[pnadmin]$ show inventory
NAME: "Chassis", DESCR: "CS-MARS-XXX Local Controller"
PID: CS-MARS-XXX, VID: V01, SN: MXXXXXXXXXXX
From the GUI - If you browse to Admin/System Maintenance/Set License/ and click on the existing License file...
You will find the Serial number in the text.