If it’s an odd factory characteristic, and the rest of the firearm is acceptable, then someone will usually want it for their collection. How much that adds to the price will vary gun to gun, and the rareness of the characteristic.

"...aspire to live quietly, and to mind your own affairs, and to work with your hands, as we instructed you, so that you may walk properly before outsiders and be dependent on no one." - Paul to the church in Thessalonica.