However, if you go to FiveSevenRedDot.com, they offer a mount for RD sights that will replace your rear adjustable sight and attach in the same place and provide a platform to attach a RD sight. I have bought mine from there and it works well. Some have had some results of the additional mass causing feed issues, but not in all cases/user experience.
It is worth checking out. BTW, it is the MKII version of the FiveSeven.