What is the price of a beretta 685 20 gauge shotgun overunder It has never been shot and is in the original box and has tags still attached?

The ref. I am looking at, Fjestad's "Blue Book of Gun Values" 2007 edition, gives a retail value of $575 for a 100% gun. At least where I live , in California's central valley, this seems a little low. It's hard for me to believe that any gunshop would ask less than $750 to $800 for a high condition Beretta o/u, esp a 20 guage..