Do a search on "Morgester" (Robert Morgester the Assistant Attorney General) here on Club Cobra and sit back with a tall drink while you read through all of the threads that he's contributed to.
Bottom line is that based on everything I've read, I wouldn't want to have replica Cobra registered in CA in unless it was registered as the actual year it was built and under SB100.
The DMV doesn't know what they're doing and will register as a Cobra as a 196X to anyone who walks in the door.
The funny thing is that the process is fairly pain free and SB100 certs are still available as of a couple of weeks ago. There's no reason not to do it.
Here's a thread with a great summary by Jamo and a link to the process steps.
A very tired subject: SB100