I'm not sure what the debate would be about, unless they are contesting the existence of the sidecar. From the
2005 California Motorcycle Handbook, on page 4 (page 8 of the PDF) says quite clearly that with a Class C license (the kind we all have) "you may operate a motorcyle with a sidecar attached, a three-wheeled motorcycle, or a motorized scooter."
Seems pretty clear to me.
Of course, he certainly has driven motorcycles without sidecars many times in the past (see
Terminator 2) and I'm sure he'll get the appropriate license now.