Pakistani techies would be capable of cobbling together fresh batteries for the stingers and the launchers. And installing them.
Looks like Osama didn't get his sh!t together on this one! A US/UK helo hit by a stinger would be a propaganda bonanza.
The heat bloom of an Apache in motion is not necessarily near the fuselage. They are harder to take down with a SAM than you might imagine. Plus, flying nap of the earth, I understnad they are barely in the flight envelope of a Stinger.
Having written all that, I agree the threat must be greatly diminished.
p.s. The Apaches are like flying tanks-- best supported by, and supporting forces on the ground. I think we have half the story here.