The Colt Series 80 design has a firing pin block, to prevent movement of the firing pin unless the trigger is also pulled to the rear. ParaOrd 1911 pattern pistols also use the Colt 'Series 80' design for a firing pin block for their pistols. The Kimber 1911 pattern pistols also use a firing pin block, although theirs is activated off the grip safety.
All of these designs will help prevent the hammer from pushing the firing pin forward should the hammer accidentally fall during decocking.
Springfield Armory, Armscor (RIA/Citadel), and most 'custom/semi-custom' 1911 pistols will not have a firing pin block. I do not know if Taurus 1911s have a FP block.
Once the hammer is down, it is resting on the firing pin stop (on the back of the slide, effectively). Hitting the hammer cannot drive the firing pin forward, since the hammer cannot smack the firing pin.