This subject has come up before, and I've looked for good images of the works of such a thing -- here's a couple shots of a JP Sauer Model 60 that's currently for sale over on the Guns International site

There for all to see, the internal significance of that "extra pin" between the fence balls and the stock wood.
Intercepting sears in all their glory dangling off that extra pin.

Thanks to the seller for the images, check out the link to the for sale ad for other images of the action, barrels, and forend.

Cheers
Tinker