Hello, I am trying to figure out how to get the leaf out of the rear sight on my son's 455 Trainer. The rear sight base is loose, and I cannot tighten the screws without removing the leaf. It looks like a pin is holding the leaf into the base, but someone is saying it is a screw, however, there are no slots or key holes visible in the end. He has his state marksmanship match this Saturday, and I need to know if this is a one way pin or what? His rifle looks like this

And the rear sight looks like this
