I had assumed our hero really did more permanently "move into" his Jake Lockley persona, adopting it as his baseline so to speak. I find it very interesting how his internal dialogue plays out (on page...16?)

He still says "I am one man. And Yet I am four." Then the first man he lists, Marc Spector, he says is dead and gone. Yet he still has to consider himself that dead man to make the previous statement true.

And Lockley, rather than the base from which he now operates, is still considered either "one of [his] covers," or "different versions of whoever I am."

So I guess in answer to my own question, it seems he knows he's not any of these people and that they are all only reflections of aspects of his true, unknown, amalgamated self.

As stable as he's shown others that he's been lately, I think this clearly shows us his footing is really as unstable as it's ever been. And while I poo-pooed any more talk of "...from the brink of madness," I can now see his inner turmoil in better definition and with greater appreciation.