So I have a Walther PPQ M2 Q4 Tac. I wanted it for the MOS option. I knew I'd lose the rear iron sight if I switched and I was okay with that but of course I would love to have both as an option. I recently came across this image of a PPQ Q4 with both as an option and I was confused. I did not see this option on any website during my search for my PPQ. I was able to find it on a website or two over in Europe but not in the US. Is it not out here? Does anyone have any more information on it? Can I purchase this slide from Walther separately?