[jhv48]

In California, it's simple. With a SPCN Vehicle, the year it is first built and registered is the model year of the vehicle. If your car will not pass smog requirements for the year of construction, then you must apply for and receive an SB100 exemption in order to legally register the car.
Out of state cars, brought in to California and registered, are currently registered as the model year that the other state legally registered the vehicle. So you could have two identical cars, one brought in from another state and one constructed in california with different years attached to them. Who cares what vin number they choose to use. And your insurance company will insure it however they want to. It will still be covered if THEY make a mistake in classifying the vehicle.
That's one of the problems with the State. No continuity! Live with it and if buying an out of state car, its registration is going to be a part of your research. No one but an idiot is going to confuse your 1965 SPF Cobra for an original Shelby. Do your homework and there will be no problems.
Until California changes its laws we're beating a dead horse.