This piece here is the only thing resembling a screw on the entire set up. I can't turn it more than a millimeter, though. When I pressed down on it with my screwdriver, though, I found the entire silver assembly, including the silver block, moved higher. It reverts back to its original position once I stop applying pressure, though. I tried turning the lever while pushing up, but it doesn't seem to do anything.
So it looks like this.
Is it possible I have to apply this pressure while mounting it to the gun? If so, that'd be a massive pain in the ass.