If the bolt is all the way back in your pics which puts the extractor claw pretty much right above that wire loop then that must be it. Judging from the shape of the ejector, it must be spring steel and has some tension on it allowing it to pop into place once the bolt comes all the way back. I would assume the ejector mounts between the receiver and the stock somehow. Have you taken the receiver/barrel/trigger assembly out of the stock yet? Looks like it's held in by all of one screw.