I think that any buyer looking for a $40,000 Purdey would have passed on this gun. Why? Because once one knows what it is that is attractive about a Purdey best, finding one that had been shot enough to go off face would be extremely off putting. If that is what happened to the metal, what about the stock? Etc.
Logic might dictate that a given buyer should pursue the gun at less than half the expected price anyway. But I would not assume the buyer is looking for an abused gun usually.
Perhaps those with more experience will address this. For example, I'm not sure I've ever found a gun that Nick Makinson thought was on face enough. On the other hand, I have shot many guns that probably really weren't on face. None were Purdeys and none were anywhere near the money mentioned.
