My hunting partner is a lefty and had Dan Cullity bring his BHE repro to his specified measurements. He shoots it quite well and has been happy with it for years. I introduced him to Dan and was with him when he dropped it off and when he picked it up. I don't remember Dan saying that he touched the finish? But that was years ago.
At about that time I had been reading about the use of hot oil to bend a stock and not having any affect on the finish, it may be that is what Dan did but I am only guessing.