I always remove a quality scope before selling a rifle. In my 40+ years of gun buying, I've only once bought a gun because of the scope on it. That was a Winchester Hi-wall in .219 Zipper Improved that had a Redfield 3200 mounted on it. The rifle was advertised as a Lo-wall and I didn't look carefully, because I wanted the scope and the price was such that the rifle ended up costing me about $150 after the value of the scope was deducted. I'd planned to part the rifle out (a Lo-wall isn't really a good action for a cartridge as hot as a .219 Zipper Improved) and I only realized the seller's mistake (and mine) after getting the rifle home. Turned out that the rifle was a custom job by J.W. Van Patten, a fairly well known custom rifle smith from northeastern Pennsylvania who was active in the last half of the 20th century. Only real steal I've ever gotten in a gun deal.