Questions was how do you know which Camarillo line you belong to. The Camarillo name is of Latin decent. It was a name given to the advisors of the royal court. Cama from camara which is latin for chamber, room or court and rillo from the word regal or royal. Most of the Camarillo's settled in either Spain or Italy and dispersed from there to the rest of the world. The way to find out which Camarillo line you come from is to look at your family coat of arms. The spanish coat of arms is in the traditional red and yellow colors of Spain and the shield has a yellow X in a red field. The Italian Crest is in Green and Argent (a silvery white) and the shield has a argent rook on a green mound with two argent dogs mounting the rook on each side. Hope this answers some of your questions.
It looks as if you are right: Camarillo is of Spanish origin. At any rate the Californian city of that name was founded by someone called Adolfo Camarillo, who was of Spanish descent.
Like most spanish sounding names you should also take note that these names are not only of spanish origin but are also of Italian origin or any other latin language, and usualy mean different things in different latin languages, Camarillo sounds like Cuccurullo which is also italian.