Mike,
Unless the cylinder stop is heavily worn, my experience is that a new case-hardened trigger will need minimal fitting.
You're using the term "Hammer Nose" when I think you mean the "finger" on the front end of the trigger where it engages the cylinder stop. (S&W calls the hammer-mounted firing pin a "hammer nose").
A new trigger and new cylinder stop may need fitting to prevent premature retraction of the stop.
