Probably not.

I'm not sure how they did it, but I seriously doubt they put bits of C4 in a shipment of devices. Why not put tracking devices so you can find and selectively eliminate targets? Given the difficulty they have finding Hamas leaders, that would be a coup. Find the leaders and the hidden bases.

That's speculation on my part. They could have done it. I'm just highly skeptical.

It's not just water or water vapor. If you can induce a dendrite (which I wouldn't know how to do), you get a short. That sudden release of energy may as well be an explosion (it technically isn't). Hypothetically, if they did put a charge (e.g. C4), they would probably have put it on the batteries. Damage the batteries, and you release the energy contained within, resulting in a rapid exothermic event.

It will be interesting to learn what happened. Should be easy to determine since there are apparently thousands of device that could be examined.