50-550 usd
The frame size of a Smith and Wesson model 66 is K.
50-500 usd
I Just Purchased a model 66-4 and mine says, Made in USA Smith & Wesson Sprinfield, Mass
With the serial number that you have supplied,your Smith and Wesson model 66-1 was made in the year 1981.
Only Smith and Wesson knows and they aren't telling.
$400 - $500.......
1976
100-350 USD
1977
Stainless Steel Revolver
K frame
square