No.

Upgrade the CAS first.

Please read the release notes for version 4.6 to see the latest information:

"Starting from Cisco NAC Appliance release 4.1(6), the Clean Access Manager and Clean Access Server require encrypted communication. Therefore, you must upgrade CASs before the CAM that

manages them to ensure the CASs have the same (upgraded) release when the CAM comes back online and attempts to reconnect to the managed CASs. If you upgrade the Clean Access Manager

by itself, the Clean Access Server(which loses connectivity to the CAM during Clean Access Manager restart or reboot) continues to pass authenticated user traffic only if the CAS Fallback Policy specifies that Cisco NAC Appliance should “ignore” traffic from client machines."

Hope this helps.