Bonding of this nipple (I assume it is not connected to a hub at one end, in the case of the meter socket above an outdoor rated panel) is required even if there is no concentric ko's. If it attached via a hub, no special bonding is required. If power companies don't want you in their sockets, and you need to bond it, either install a meyers hub on the panel, or install a grounding bushing inside your panel, or use a pvc nipple. Just make sure to bond the pvc with a nylon jumper!(ha-ha)
Rick Miell