There are plenty of steel night sights available.
I recommend Meprolights or Trijicons.
My P99 has been thru 4 different training classes, and the Trijicons I installed are still attached, and working perfectly.
Just push down on the plunger and slide the Meps into the dovetail, they take a fair amount of finger pressure to go in, but no tools are required.
My Trijicons have been thru ####, and they are still attached, and they were pretty loose in the dovetail from the start., the Meps are a much tighter fit in the slide.
My Trijicons have been used in hundreds of one-handed racks, where the rear sight is hooked on my belt or holster, and used to cycle the slide, and its not gone flying yet.