Referenced product: SIGHT-FLIP-FRT-1
Based on our product photos from when Sig first started offering the MPX, it appears that the sight is the same or nearly the same as the ones Sig included on the MPX. It should be compatible.
Referenced product: WMPX-K-9-KM-PSB-FDE
We haven't run MPX's out past about 30 or 40 yards. The maximum effective range is going to depend on the bullet but probably would be somewhere between 60 and 75 yards.