ID? He could falsify some, as he is doing this projection, but without a solid to base it upon any such illusion would be just that - illusion. Nothing that would, in the end, please this officer. It might stall her, but...

He still makes the 'effort' to look. It gives him a moment to stall and try to come up with something.

"I...appear to be missing it."

Optimus has never been a very good liar. Which is why he's telling the truth.