Since I started this thread, if I may....
My issue was not so much if the Pietta tail was correct, or close to it, but more an issue of taste. It feels and looks awkward in the extreme to me. If I was to purchase a new Pietta Navy with the extreme tail, I think I would have to make it go away for that reason more than any.
I realize that Colt hand-fitted most of the Navys and no two craftsmen are the same, so it is likely that several different profiles might appear. However, Pietta went overboard in the extreme in their rendition and I don't care for it.