Seeing as that CA isn't quite sure what the new laws mean at this time, you're on your own and it doesn't look good.
I would think that since the USC, and SL-8, have only 1 ugly feature (pistol grip/thumbhole), that they would be okay, once the CA AG figures out the legislation. The magazine is detachable, but it is not capable of accepting a magazine with a capacity greater than 10 rounds (per ATF specs, can CA argue with that?).
It's wait and see time.