Screw in choke tubes, on a classic double, stress classic double, eliminate it as being a classic double for a vast majority of potential buyers. Not kidding when I expect that group to be in the 80-90% size. You have removed the classic charm of the side by side and made it into a practical gun many will not be interested in buying. You might still get full value out of the gun but it also might take even longer for a purist to decide to buy it. If ever.

Hard black chrome is a much more durable finish than slow rust bluing but if you put that on a classic double or a nickle finish on a receiver you will struggle to sell it to anyone but a shooter seeing it as more low maintenance. Same thing with screw in choke tubes.