Here is some good info for you,,,
Click here please,,,
Basically what you have is a Stainless Steel version of a Model 19,,,
That's the K-Frame .357 Magnum.
According to the 2010 Standard Catalogue of Firearms,,,
This is what the book has to say.
Model 66 (.357 Combat Magnum Stainless)
Released in 1970, this is the stainless steel version of the Model
19 or Combat Magnum. It is chambered for the .357 Magnum,
has adjustable sights, a square butt with checkered walnut grips,
and was initially offered with a 4" barrel. In 1974 a 2.5" barrel,
round butt version was made available. It was available in a 6"
barrel, as well as all target options until discontinued in 1993.
NIB Exc. V.G. Good Fair Poor
500 310 250 200 150 125
Hope this helps,,,
.