RME within the CW2000 bundle have various reports like the Hrdware and the Detailed Device Report which can show the device serial# provided you first add the device in the RME Inventory and it goes to the managed state. For XL switches and Switches running CatOS, RME will automatically pull the serial# since both of these show the serial# in the 'sh ver' output. You can also do a telnet to the switch to verify the serial#.
But for routers, you first have to manually add the serial# in the router config using the command snmp-server chassis-id before RME can poll it. This tech tip would clear things up in detail: http://www.cisco.com/warp/public/477/SNMP/chassis.shtml
Alternately, you can also update the device serial# manually if you're using RME by doing the Change Device Attributes and enter the serial#. After that running the Hardware or the Detailed Device Report would show these. Hope this helps.
