Well - YMMV.
While I wouldn't take a shiny/silvered gun out hunting, I might shoot one on the range - but who knows ?
If it's one of those "specials" (i.e., verified in writing by Winchester), it could be more valuable to someone who collect such, fired as little as possible.
Keep in mind that NO guns are truely unfired - since the factories usually "proved" them by shooting at least one shot through them. (Some states now require that fired case be kept/sold with the gun for handguns, IIRC)
FWIW, In over 50 years, I've never personally changed/damaged ANY firearm via simply firing it - at least enough that anybody could discern.