I'm no expert, but the quality of wood used in KP stocks is so far superior to original S&W wood that they are easy to spot.
One of the things I've found lately (deep in the depths of my old stock buying binge) is that it's really hard to "get" a lot of these grips and stocks without handling them.
Even some of the better write ups on things like palm swell and the little nuances involved in old Ropers and KBs just can't be conveyed with pictures and text. The quality and workmanship also isn't something that you can quite get until they are in your hand.
My latest set of Ropers for example:
Look amazing right?
If you look closely you can see how they were clearly hand made:
Don't get me wrong, these little details are why I absolutely love these grips, but you can tell that Gagne, for all his talent, was making a set of grips for functionality. The checkering pattern was a nod to beauty, but also (I'm just guessing here, this is my opinion) a trademark. That lovely ribbon pattern says ROPER. It also happens to be pretty. The wood though? It's nice, but not chosen for beauty.
A set of KB stocks will be a bit more obsessively perfect then Gagne's (in my limited experience, talk to me again in 10 years when I've had a chance to handle more then 6 Ropers

). Still clearly hand made, but with much nicer wood, and more of an eye and focus on making them beautiful in addition to functional.