"The book" may have no emotion attached, but it also has no connection to reality. The reasons people value things is completely irrelevant.
Yes, I've seen gun stores show the book values in an attempt to get you to believe their offer is reasonable, but calling them reputable is a stretch. I also had my insurance company offer me a low-ball claim for a stolen S&W revolver based on the book value, when I showed them what they were selling for and ask them to find me one for what they were offering, they increased their payment by $300. Absolutely, insurance companies and gun dealers love the book values that are 2-3 years behind today's real world value.
Throw away the book. They are worthless in determining real value.