Looks like a custom OEM microphone of some sort, getting an exact substitute is going to be difficult without more info on the mic itself. That's why they are selling it for such an expensive price! You can buy electret gooseneck mics for under $100, and that's probably what the value of this mic really is, but without knowing the specs, it's a crap shoot whether you can find a substitute.
It would be easier to replace it with a standard mic jack + microphone than trying to source a replacement, unless it's some kind of proprietary connection.