M&P and SD sights
are fully interchangeable. I use Warren Tactical rear sights on all of my M&P's and already have one on order for my SD9. I much prefer the plain black rear sight with a tritium front, but I don't use F/O. Instead I go with the Ameriglo ProGlo tritium front with the orange or green ring. This is a pretty similar set up to how I have all of my M&P's right now.