This is only my opinion and others may disagree and that's perfectly fine as we are most likely using it for much different guns.
I believe that this (fantastic!) reference book hasn't had much decent market value use for many years. I mean to say that the book and all the information inside is certainly of fantastic use, but as a
price and value guide, it is outdated and in some cases, it is extremely and shockingly outdated.
To put it another way... for the guns I seek, if a dealer has a table with handguns on it and I ask about the price of one he doesn't have marked and he picks up the big Blue Book (any edition!) then I already feel like he's entirely out of touch with the real current value of what we are looking at.
But again, I'm not likely asking him about a S&W revolver from 1952, we are looking at more modern guns.
As an informational resource, the Blue Book is legendary. As a market price/value indicator, it has a legendary history but that it is or should be long retired. I will reiterate for anyone itching to say I'm wrong

but I'm talking about modern guns and scarce variants of modern guns.
I like to pick up a Blue Book when I see one that's selling for two bucks in a used book store. It's terrific for identifying things and often for finding a "last known MSRP" but as a price guide, much of it is completely irrelevant.
We had a similar discussion with Jim Supica with regards to his (and Richard Nahas) phenomenal
Standard Catalog of Smith & Wesson. He made it clear to us that his publisher basically
demands that it be considered a price guide, because that is simply how it works in the publishing business, but we all know (and the authors do as well) that it is a killer reference and identification guide, and to keep on top of market values is nonsense, the market often changes between final submission and printing/distribution. Add to the fact that the newest 4th Editions of the book came what, 10 years after the 3rd Edition?