ipod stolen, need serial number. no backup device found on itunes?

Ipod nano stolen, needing serial number for police report.

tried the advice of going to itunes and doing "if you hover the mouse pointer over the backup for the iPod in iTunes>Preferences>Devices the SN will appear in a box."

the Device Backup box is empty, leaving me with nothing over which to hover, no serial number found.

is there still a way to find this number through itunes? nano was purchased 5 years ago and definitely don't have packaging/receipt...