I'm going to offer the opposite opinion for several reasons.
You are looking at a gun that is no longer made. That means the only ones available for purchase are the ones that someone else already owns, so there is no gun shop around with a dozen of them in inventory on which they are willing to take a short deal in order to free up some operating capital.
Next, it is a pre-IL, pre-MIM Smith & Wesson revolver. Such guns are in higher demand than ever. From point number one above, you know that the supply of such Model 66s is not great. You also know what happens when you combine a declining supply with a rising demand.
The gun you seek has a four-inch barrel, probably the most in-demand length for Model 66s. See point number two.
It has a pinned barrel and recessed chambers. Read point number two a few more times.
If by its serial number one can assume that it has a stainless steel rear sight like the one "mbliss57" bought, it is an early production gun, a lot of which were never made. Another half-dozen reads of point number two might be in order.
A lot of us can show you Model 66s that we bought just a few years ago at what seem like bargain-basement prices today. I'm no exception - from top to bottom, the three in the photo below cost me $436, $540 and $416 plus shipping on the bottom two and sales tax on the top one. At the time, $540 was a lot for a Model 66 while $416 was a steal for a snub.
Now, in fairness, I must tell you that none of them came with the nicely-figured factory stocks you see on them now - the two longer ones did have their original checkered target stocks but they weren't as nice as those and the 2-1/2" gun had Pachmayrs on it, so I have invested, on average and after selling their original ones, an additional $50 in each gun. The 4" and 6" guns came factory-equipped with target hammers and triggers and the 4" also has a trigger stop, something that is not often seen according to the more knowledgeable folks on here.
So yes, some of us were smart in hindsight or just lucky, as in my case, to have bought before the values of these guns rose. But if you want one and found a really nice one, that sure wouldn't stop me from paying what others might consider "too much" for it.
Bought any all-original 1964-1970 muscle cars lately? They were cheaper once upon a time, too.
Ed