like I said, I'm not sure about having to serve you before they can act on it since it really isn't a new judgment so to speak but merely allowing the judgment from Oregon to be enforced in California. If they do not have to actually serve you before then can initiate actions to garnish, they may get your money before you can stop them if you do not act proactively.
I would file an action with the courts to seek to have this California judgment set aside due to the judgment it is based on as been set aside.