...Plus I don't consider sharpening a knife a "modification" to the knife, especially not the way you sharpen knives. Some people might think otherwise, however.
I went to a gun and knife show many years ago. The "collectors" did not value any knife that had ever been sharpened as much as one that had not. I was trading a Case Bowie in really good shape for a CS kukri. Because I had sharpened it, I had to pay more in difference. Also, I have noticed on evilbay that "Never sharpened" is a selling point. To me, this is stupid, unless the knife was poorly sharpened or had a damaged finish. It seems to hold true, though, even among Busse collectors, that an unsharpened one is more valuable.