The GS is a King's Custom Gun Works #203. Yes, it works with the standard hammer, but you will have to bob the hammer a little bit in order to allow the slide to clear. It does have about a 1/8" gap betwen the grip safety and frame tangs. I like it b/c I didn't want a commander hammer and the gap doesn't really bother me. What's important for me is that it prevents me from getting hammer/GS bite on my hand.