if they didnt puncture the felt on the diaphram casing then chances are the diaphram is ok. if they poked through the felt on the cover then there's probably a problem with the mic and it is more than likely not worth the trouble to fix. By the way, im not talking about the felt inside the ball, im talking about the felt on the chingadera that you see when you take off the ball.

chingadera? what is this word? i've never heard it before

but yes, i know what you're talking about. if I had seen a diaphragm there instead of foam i probably would have gotten scared and put the ball back on.

but could a few taps on the diaphragm, or even the little foamy thing that's there, cause an increase in sibilance? this is probably a horribly arcane question

really it sounds fine most of the time (does mic placement affect sibilance on vocals?), and I don't use it for vocals that often anyway.

i really doubt a few taps on the top of the housing is gonna cause any problem...those sm mikes are SHUREman tanks. I wouldnt worry about it.

- really it sounds fine most of the time (does mic placement affect sibilance on vocals?), and I don't use it for vocals that often anyway. -

Yes, mic placement affects sibilance a whole lot. Even 3 or so centimeters to one side or the other would incresease/decrease sibilance.

Try this :
Start hissing (like you were trying to say "ssssss"), and move your head gently around the mike. Have someone monitor your voice through headphones, or record your hissing. You'll see what I mean.

And no, you can exert a LOT of abuse on the housing of a mike, without any problems. (by abuse, I don't mean using it as a hammer! :-)