I happen to have a sacrificial 5330 here (intentionally broken display, unfortunately,) so I took it apart for my own purposes - mostly to figure out the mechanics of the buttons.
Anyway, I just took a closer look at the mic unit. It appears to be a piezo element, so the diaphragm is metal, not foil, as would be if it were an electret condenser. I poked a paper clip at it pretty good and there doesn't appear to be any damage, though for obvious reasons, I can't test it
There's a cloth filter, too that you'd have needed to poke through as well. Pics available if needed.
-dg