Personally I don't mind small restorations or cleaning as long as they are
- honestly documented,
- fitting with the style of the original,
- don't alter the handling characteristics or change important features (like removing markings), and
- are non-destructive as much as possible (with the understanding that in some cases you can't very well keep the original, e.g. restoring a grip that has just a tiny remainder of rotting wood left on it), and
- preferably reversible if possible.
But I really don't like it when I find out I've bought a fantasy composite of old (and new) parts after the fact, or when people take apart old swords that are still largely intact in order to harvest parts.
In this case I don't think I would mind knowing that either the nose or some of the silver was a replacement (but I would personally keep it as it is since I quite like it and I don't feel the missing bits detract from it).