depends on what your position is...buyer or seller
Over all the years I've been involved with this firearm collecting, shooting, buying, selling, etc. arena, the one thing about "gun price guides", books, catalogs, etc. is that it really depends on whether you are a seller or a buyer, as to the guides perceived value as a tool.
Having been both a buyer and a seller (like most of us) I always saw sellers use Blue Book to show potential buyers how much on the high end the gun is worth, then stating that's an average value, then touting the rarity, scarcity, ultra fine condition of their specific example whereas buyers try to convince the seller (usually a no-go) that the gun is at the low end.
Normal market negotiations in a capitalistic society. Check out Kelly Blue Book for your car/truck value..you think it is perfect condition (high value), you want to get the top private sale price, the dealer goes with average to below, just like guns, so as posted by others.....the truth is somewhere in between and the best price is one that leaves both parties satisfied when completed.
I've found that lately the hyper inflated prices on GB (completed auctions only) etc. can be a starting point, but I sell pretty much only locally, or here on the Forum, and if you priced too high...nobody buys...so the "market" sets the real end price.
I quit buying Blue Book (Fjestad) years ago, but my old copy along with Standard Catalog of Firearms (Jerry Lee), Gun Digest, do have some good reference information, and like the miltary sections don't go out-of-date on serial numbers, variations, etc. but none are close in pricing.
Invest whatever the BB sells for today, in a membership to SWCA, and enjoy all the benefits of tremendous knowledge and help, right up to date, with the click of a mouse....including pricing! WE CAN HELP you spend your money if you are in a buying position, AND the Forum Guns for Sale sub set is a real good place to either move your guns, or find you are priced too high.
Just my $.02