You will not need to add any additional smog components to your Chevy Caprice in order to make it California compliant. There is a difference with California legal and Federal legal emission requirements, however if your Caprice is equipped with all the Federal required emission components (which it was originally equipped with) it can pass the California smog check and register with the CA DMV; as long as its emissions are below California emission cut scores.
The rule is that used vehicles which are equipped with the necessary Federal Emission Components are eligible for California registration as long as their exhaust emissions fall within California's limits and the vehicle emission systems has not been tampered with.
