A couple of points, too long for comment, but not meant as a complete answer.

Tidal locking doesn't mean zero angular momentum.  The Moon has angular momentum.  It rotates at nearly exactly the same speed as it's sidereal orbit, every 27.3 days.  The Moon is also unusually lopsided, it's near side being denser than it's far side, but I think we can ignore that aspect for your question.   Tidal locking requires rotation,otherwise, we'd see different faces of the moon as it went about it's orbit.   Tidal locking appears to be zero rotation, but it's not.

If you imagine the Moon flying past the Earth and you imagine each of the two haves of the moon with their own centers of gravity, two things will happen as the moon flies past the Earth.  The near side will be stretched towards the earth more than the far side, creating a tidal bulge and the near side will be drawn towards the Earth faster as it approaches, creating a reverse rotation, if you will, but as the moon then flies away from the earth, that tidally driven rotation will be reversed.   

In the example you give, of the moon flying past and being captured by the Earth, then there should be a permanent, though small, reverse rotation, at least by though experiment, driven by tides.   This effect would likely be quite small and would depend on how close the final orbit was.  A few miles per hour, maybe a few tens of miles per hour, but with a fly-by to orbital capture only, which was your scenario.  A near pass-by wouldn't have much affect, though there could be some due to tidal bulging and uneven mass distribution, that that effect would be small.   (This is a thought experiment answer only, I lack the skill to do the maths.)