correct
CME's have no classing system at all
the light emitted from a flare can be registered and monitored here on earth as well as on satellites
for this reason, we have a classing system for them and how strong they register on the monitors

a CME is mass ejected from the surface of the sun and hurled into space and they travel at carious speeds
we can not monitor how strong it is until it hits our satellites and monitors on earths surface
for the CMEs, we basically have to go on its speed, direction of ejection, amount of mass (this we use STEREO, SDO and SOHO to determine

but it sure would be nice if we had the technology available to class the CMEs in the same manor that we do solar flares