We don't run CME except in the lab so I'm not an expert here
We do know that device firmware versions are not dependant or
related to the specific CME/IOS that you are running so you should be good to go.
You could always try to upgrade the CME with the matching firmware just in case
you add new phones and want them to have the same loads.
"May your heart always be joyful
May your song always be sung" - Bob Dylan