Hi -
Cisco Partners and resellers have access to a tool called the 'Service Center Center ' (SCC). You can get to it at www.cisco.com/go/scc, and login from there. Using this tool, you can search for serial numbers and it will tell you what type of device you have and if it's covered by SmartNet or warranty.
That's about the only way I know, other than getting in touch with your local Cisco sales rep.