Built-in microphone?

Please Mod create a section for Virb hardware, otherwise Virb Edite sections will be flooded by hardware discussions.

I have noticed today that the camera holder on the "lower" side (the one on the connectors side) is asymmetrical, on the left there is a kind of "protrusion". On that side I noticed a small hole, closed by a small rubber part, I guess in correspondence to the built-in microphone?. It looks like that rubber part can be removed. If it's not the microphone, could it be the hole bringing pressure for the internal barometric altimeter?