No, the brass pins as you call them actually are little hardened pins. They prevent the slipperplates to slip on the pressure plates. You should use both the slipper plates and the pressure plates.
Yes, you are correct. The slipper pads can fall right off.
I guess I'm missing the slipper plates. So it goes the pressure plates then the slipper plates and they mate against and sandwhich plastic plate on the strobe. Right?