Any information in any email or document might be classified even though it bears no marking. She would STILL be guilty of felonies in this case and I suspect there were a lot more instances like this than there were of the ‘(C)’ instance.
Don’t forget her emails ordering her peons to strip the secret/classified/top secret classification before sending through her server.
These (C)s are very easy to find on a document. No excuse for missing them.