No Colt support for Mark V's, at least when I called Colt CS and asked a few years ago. I replaced firing pin springs last year and picked up a set of spare firing pins from GPC for both my Mk V Lawman and Trooper.
As cited, those Peacekeepers were mostly strike period guns, just like the matte finished (parkerized looking) Colt Agents and Detectives of the strike era. Seen plenty of those guns that got out the door with off center barrels and poor timing.
My Lawman Mk V was such a strike gun, out of time and badly off center front sight. Karl Sokol reworked it for me about 5 years ago and re-clocked the barrel and fixed the timing, new hand, etc. It is a really good shooter now but I don't dry fire my Colts anymore.