I recently purchased a WZ.29 missing it's front sight blade - the base and ears are still there - and sourced a replacement front sight assembly which should arrive soon. One question, I can't find any good instructions for installation - looking at the base it's obvious the blade slides in from the back, but I can't figure out how it's secured. Maybe it'll be obvious when I have the complete assembly, but just in case, how do I install it?