The conduit fill is fine but the #6 is not required and will be of little value in a fault. the service pipe gets a bond bushing and the neutral is bonded in the meter base and again at the main switch so adding a #6 only parallels the neutral and the service raceway. I would only add a bond wire if I used PVC as the service raceway even though the neutral meets the minimum code for bonding the meter and mast to the panel. Many inspectors would insist on a bond wire if PVC was used between the meter and panel but it is not required as the grounded service conductor serves both purposes until the neutral bus in the main panel.
