UNLOAD your gun. Cock the hammer, and then look into the recess where the firing-pin falls. Instead of just a 'hole' for the hammer-nose, you will see there is a 'track' of sorts. A beveled raceway both above and below the hole. This is to guide the hammer-nose into place.
That up-down play is perfectly normal. What you may look for is side-to-side play. If that rivet that holds it in place has loosened, it may be able to be tightened. I had instructions on the old board for installing a new nose, and it's rivet. Perhaps that's archived somewhere?