Here's what I have for a track
Smith & Wesson 617 Plus Revolver in .22, Long Rifle. Bluebook of Gun Values (30th Edition) indicates between $476 in 98% condition and $633 in 100% condition for this gun. I have 43 recorded prices for this model gun from $350 to $729 over a period of 6 Yrs 5 Mos ending March 3, 2010. The average price as of that date was $464. No refurbs, no refinishes, regular sights, all represented as 95% or better, no distinction for engineering revision, if any, no special editions, no distinctions for box, papers, tools. Current or last MSRP is $940.
Here's the chart (two months shy of the track data):
So, with the average price trend at about $580 as of January 2010, I'd expect +/- $50 depending on the condition of the gun, presence or absence of box, paper, tools, etc and maybe a little more on the high end because it doesn't have the internal lock. The Bluebook would knock off $16 for the 6-in barrel if it is a six shooter.
Given the way the 617s have appreciated against inflation, the future value is somewhat attractive, too. The average 617 has appreciated at a rate of about 6.816% APR (that's compounded monthly) over 77 months. If that rate holds, a $700 average price would show up after another 40 months. That's better than most money market stuff right now.