Answer

It depends in what sense. A resident alien must accept upon himself the seven commandments before a religious court, and that requires belief in the revelation at Mount Sinai (see Maimonides, end of chapter 8 of the Laws of Kings). But the status of a human being who is entitled to proper treatment can apply even to someone who does not believe in the Torah or in Sinai. Just like a secular Jew who does not believe in that.