My inquiry is solely directed at the nipple, and only where concentric rings remain. The meter socket is factory bonded, so the bonding bushing, which I install only on the disconnect side is to bond the nipple to the service disconnect which we are required to bond. My observation has been that the bonding of this short section of service raceway has been ignored. Similarly, in off-peak systems where 2 meter sockets are nippled together, I rarely see the nipple bonded.
BTW,
PECO doesn't want any bonding wires in their sockets either. This poses a problem when entering into the side of the socket with remaining rings.