Hi Dan,
I'm afraid the central manager doesn't show the serial number of the devices anywhere. This information is only available from the CLI.
From the central manager, you have the option to launch show commands remotely to a device (through the device "troubleshoot" menu). You could use this feature to run "show inventory" or "show hardware" remotely and get the serial number information from there.
There is already an enhancement request in place to add the serial number information to the device details, but, for the time being, I cannot give you an estimated time for this feature to be implemented.
I wish I could give you a more satisfactory answer
Daniel
