I've got 5 or 6 Troy rear flipups, so I'm not sure how old this one is. Was mounted on my 11.5 BCM upper, and in the process of punching out the FSB pins the sight fell apart. First time any of my Troy sights have given me grief.
update: Troy responded quickly to my email, asked for more pics, I sent them, and they responded with instructions on how to re-assemble the sight. I'm gonna take a crack at it tonight.