EDM
If a "knowledgable dealer" does not see a rifle barrel that has been relined and a scope that is buggered up with mounts that are a mess should you hold him accountable? I can see cutting some fellow who does not know guns from butter missing the items described but not a dealer who knows his butt form a whole in the ground. The dealer, "in the trade", needs to look at what they are selling and be honest in answering questions that are asked. We are not talking about a fifty dollar item here.
Fix what needs to be fixed, or state what are the problems in the listing. Easy to do. Tell the truth when asked. Again, easy to do. When you make a mistake and cause someone to waste time and money in shipping a gun two ways refund the shipping if it is your fault. Not asking him to do this for a gun returned simply because the buyer changed his mind. Seller screwed up by either not answering the questions honestly or by not spotting basic things that we all suspect he could spot very easily if he tried. You would not put up with this from a car dealer. Why should you do it from a gun dealer?