No this is not possible. Central syncs the entire device inventory between your Activate and Cental account.
All devices are synced without a license assigned, unless you activate auto-assignment in your Gobal Settings. Only when you assign a license on Central, it will establish a connection to Central.
If you pay close attention on Activate, a device is actually moved from the default folder to another folder, once you assign the Device Management license. This folder has the provisioning rules configured.