Well, from my experience as a collector for over forty years we have to ask ourselves the following questions... and I like to stick to my own general formula...
1. Does S&W make them anymore? (+ or - $200)
2. If they make anything similar what is the retail price? (+ or - $100)
3. What is the condition of the firearm being considered? (+ or - $200)
4. How many do I see popping up in my area and how many have I had an opportunity to buy. (+ or - $100)
5. What additional costs will be tacked on to the guns purchase? (shipping, FFL fees, etc). (varies)
6. How much more expense and time will be incurred in my search to find a similar firearm for my collection? (varies)
IMO, throwing a decision on a quality gun purchase to an anonymous group of people who may or may not have any knowledge of accurate value or market availability can be a true exercise in futility.
Sadly, there is no "Kelley Blue Book or NADA" book, published bi-monthly with
current and
always changing market values for guns like there is for automobiles. We've gotta consider or own needs, desires and common sense to determine what a purchase and its pricing is best for us.
Just sayin'