Dr Bill, asymmetry of fading has been reported widely to be common, and the side away from the wall has always been reported to be the faded side (at least in the reports I've read). The sunlight-fading believers cite that as a point of evidence.
However, I have a Lefever G I bought at a very good price because of an uncommon problem: It is in excellent condition all around, showing little use, with perfect bores, but the nicely-figured Damascus bbls have fingerprint corrosion spots and not just a few. No perceptible depth, but requiring a refinish (which I will do).
Its right lockplate has considerably less finish than the left, and the frame has very little, particularly where a right hand holds it to carry it. There is also an area of minor corrosion, where a right-hander's fingers naturally curl under the frame.
I don't know what somebody had on his hand but it sure wasn't finish-friendly.