THE GUN IS 100% FINE
colt is using some 80series parts in the 70 series ... the hammer is one, so is the firing pin, and extractor, maybe even the sear and grip safety.
they do this so they wont have to go through the trouble of producing 2 SLIGHTY different parts and have to deal with making sure the 70 parts go to 70 guns.
the way to tell a 70 from an 80 hammer -- the 80 hammers half cock notch is a flat "shelf", on the 70 half cock notch shelf there is a small "hook", you can feel it with your finger nail. the hook prevents the sear from sliding off and letting the hammer pop back up. your not supposed to cock your gun to "half cock" it supposed to catch the hammer if your thumb slips, and squeezing the trigger allows you reset the hammer fully forward Safely, rather than full cock the hammer and thumb it down, which shouldnt be done.
also if you were to pull out the firing pin and extractor on the guys 70series, you will find slot cuts in both parts for the 80series firing pin block.
on the grip safety the tab that sticks out and pushs up on the sear, the 70 will be wider, the 80 narrower to allow room for the levers to push up on the firing pin block.
on the sear the 80 will have a small hole in the back from the gold cup spring which prevents the sear from bouncing while racking the slide and hurting the trigger pull (a custom target gun mod), and maybe a small square notch on the edge.
actually while colt was transitioning from the 70s to 80s, they produced a few 70 series guns with full 80 series parts and firing pin block. the 80 hammer really doesnt have anything to do with the firing pin block, its a thing they changed in the late 80s a few years after they changed to 80series guns. you can interchange the 80 and 70 hammers with no problem.