My answer is Maybe. Since we are talking about Service Entrance conductors our conductor size is based on T. 250.66 or possibly 12.5% of the phase conductors. Depending on how the job is installed, you might end up with an external bonding conductor and bonding fittings on the flex. Actually I could use more details before a final call could be made.
Notice that if the entire run is LFNC no bonding conductor is required because the GroundED conductor takes care of that.
