Failing the Turing Test

If a robot develops self-awareness, and has a lifelike shell, can it be distinguished from an actual human?

Yes, because no robot could be programmed to interact just like a human. Humans are almost completely lacking in self-awareness, and so they would be very bad at that sort of programming. They find it hard enough to program a robot to see an object, as an object.

Furthermore, humans have evolved to be able to assess each other for sincerity very accurately. So they would be extremely likely to pick up on such bad programming. So the question arises: how would a robot with self-awareness be distinguished from a human?

The clue is in the question: such a robot has self-awareness. And so if you ask it about itself, then it will know about itself. Whereas if you ask a human about him or herself, they will not really have a clue.