That's a good question. I haven't made up in my mind which makes the better idea, even though I have run both plots/thought experiements.

For the purposes of this poll though... no Mike doesn't know, as Joel's vaugely calling himself something like Joanne in public to better go by unoticed and hide from the MADS and so on.

There's also a bit that explains that Mike is from normal cannoniy, so he knows Joel, though a diffrent Joel than the Joel from this particualar alt universe - but it gets a bit complicated. = )