I don't know. According to what I have read in the teachings, someone who's not enlightened can't recognize an enlightened person. However, we could see if someone is not enlightened I suppose. According to the scriptures, an enlightened person is unable to go against the basic Buddhist Morality, and that is the Five Precepts. And so if a person says they're enlightened and they're not keeping to basic Morality, then one could have doubt.