You really need to create them manually. You can use the following SQL statement.
If you want to find all W2K workstations, just change the version number to 5.0.
select SMS_R_System.ResourceID,SMS_R_System.ResourceType,SMS_R_System.Name,SMS_R_System.SMSUniqueIdentifier,SMS_R_System.ResourceDomainORWorkgroup,SMS_R_System.Client from SMS_R_System where OperatingSystemNameandVersion like "Microsoft Windows NT%Workstation%5.1%"