Insurance Coverage Q&A: Determining a Value for Old Books

I have an Insured who had a fire loss. In the house were old hardback books that belonged to their parents that were worth over 800.00 a piece, according to the internet when I looked them up. I would imagine that they were new when purchased 50 years ago. Some of them no longer have the jackets to them. The adjuster is wanting me to find a book appraiser to see what their worth is according to the condition that they are in now. That would mean the homeowner driving to Chicago, IL from South Bend, Indiana to do so. There is also a book by Erma Bombeck (hardback) that isn’t in production anymore, but Amazon has it for sale new at $400.00. What is the protocol for book replacements? Again, this is the only insurance company that has made us do this. They normally take the replacement cost price, depreciate it by the years of age and give us the ACV.