In addition to those mentioned, Earl Lanning, Mel Hankla, Jack Brooks, Mike Brooks, the whole Woodbury school and a bunch of others are good at aging wood realistically, building up some gunk, showing wear areas, etc. Most try to achieve the look of a stock that has been well-used but not dried out. The dried out look of an attic condition gun is not so attractive. I think what most are going for is a "still in active use" look, a gun that has years or decades of wear but gets rubbed down now and again with some oil, like a current user would do to maintain a working gun.
On the metal, especially the iron, I don't like the "uniform pitting" look, and prefer something more like what happens on real guns in use- some areas shined off, some areas with some original finish intact, and areas with pitting where it belongs- at the breech end, where water and dampness or fouling sits on a barrel or lock.
