I bought this one, dating to about 1971, a couple months ago with two magazines for $1100 out the door, IIRC. It was priced right and wasn't a scream right off the shelf deal.
They were selling new ones for about $1400 out the door. I'd have paid $1400 for the used one before I'd have paid $1400 for the new one. They really don't make them like they used to.
With most firearms you can look at recent completed auctions of Gun Broker and get a fair idea of current market value, but with the S&W 41 it's hard to do that.
There are variations in age, barrel length, contour, muzzle brakes, etc as well as the usual with or without box and with or without cleaning tools, hang tags etc that will throw the actual final bids all over the place.
In the end, it's worth exactly what you are willing to pay for it.
I'll also add that with firearms that are no longer made, or are no longer made to the same level of quality, you rarely pay too much, you just buy too soon.
For example, I bought an earlyWinchester 9422XTR for $700 about 8-9 years ago and the general consensus from the blue book crowd was that I paid too much. They were placing the value down around $450-$500.
Today an early 9422 XTR in that same excellent condition will sell for $1350-$1500. Did I pay a little too much? Maybe $50-100, but not nearly as much as blue book references suggest. Blue book values are flawed for a couple reasons:
1) they are old before they are even printed and published; and
2) it's a "blue book" value intended to help retail sellers, who will buy one with an intent to turn around and sell it at a profit.
So…if you want it, buy it. Unless you plan to quick turn it for a profit (and if that's your intent you need to have an FFL), you won't lose money on it. And unless you find another like it for less money fairly soon, when you do get around to buying one you won't pay much, if any, less for it.