Just to keep things clear and accurate, Freud has nothing to do with an idea of being an authentic self. I'd have to ask which text of his you have in mind.
It is probably too late, but he did have a lot to do with our placing such a high regard on our inner, immediate emotional life. You are right, he said nothing (that I know of) about authenticity directly, though I think he was very much in the "express your feelings" (whatever that means) line of western thought.
