Prices are rising on the older guns as more people scoop them up in favor of the new ones.
I see a lot of "What's it worth?" & "Did I pay too much?" questions on various forums. The answer to that, in the escalating market, is very simply "It's worth whatever you're willing to pay for it if you want it bad enough before somebody else grabs it." I tell my brother-in-law when he asks if a particular older Smith is "worth it" (he's picking up a few, too) that "It doesn't matter what it's worth, how bad do you want it?"
Prices & availability vary from region to region, and the blue books are not particularly helpful any more.
I've snatched up a Pre-14, a 25-9, and a 586, all six-inchers in 95% or better shape, over the past year or so, and considered myself lucky to find 'em. I'm far from independently wealthy, but I've had to face the fact that the guns I want won't be around much longer, and I have to do what it takes to get some of the classics while they are.
Getting to the point where, if you wait till "someday", or pass on a good one here today because you think you can find one for $50 less someplace else tomorrow, you're going to find yourself high & dry.