Help with Elgin 18s grade 27 pocket watch. Odd winding wheel fastner.

[MrRoundel]

Greetings all.
I recently picked up a nice Elgin 18s grade 27 movement. It seems to be a very well made grade, with interesting, probably patented, features. It has some minor oxidation here and there, but seems like it'll be a runner after a basic service. I'm at the point where I'd like to remove the disc shaped gear (Crown wheel? At roughly 12:30 in image.) that meshes with the winding pinion but it is held to the plate by a different sort of fastener. I'm guessing that it threads on and off by using a wide, thin, screwdriver or special tool that I'm without. Is this correct? Does it thread? Is it standard a right-handed threaded part? Any help or tips would be greatly appreciated. Many thanks! Cheers.

[MrRoundel]

So just in case anyone ever runs into this, the fastener certainly does thread on. It is removed with a thin, but broad, screwdriver. The trick is that it has left-handed threads. I asked because I didn't want to force it. Rick H. over at the NAWCC verified that it was indeed threaded. Cheers all.