I don’t know about OCS, but to register your car on base I didn’t have any problems in Quantico with the registration in my dads name. NAS P’cola threw a fit – I ended up changing it into my name. If you get a notarized permission slip from the registered owner saying you have full use permission to use the car, you will not run into any problems so long as you have the registration, insurance, etc. It may not be completely necessary, but a lot easier done before the fact than after.