I think a vet check is a good idea with a stool sample. Although some small dogs do make big bowel movements. I had a Maltese who had very large poops, it always amazed me that a little guy could make such a huge poop.
If you want to sell it quickly, you will have to price it fairly. Be honest when you go to Kelly Blue Book about the condition, this will give you an idea of what to ask. Get ready to haggle.