You can see the red plastic insert in the ramp front sight. Inserts of this type are good things in any front sight, as they offer both color contrast and high durability. Painted front sights chip and otherwise wear, but tough plastic inserts just keep on keepin' on.
You can also see that the rear strap of the Model 66 grip frame is grooved. The front strap of the grip frame, which can't be seen in these photos, is also grooved, as is typical of the Model 66.
This particular handgun is quite accurate, which is no surprise, as most S&W revolvers are accurate guns. The single-action trigger pull is excellent, breaking at 3.75 to 4 pounds according to my RCBS Premium Trigger Pull Scale.
The double-action (DA), although not quite as slick as a Colt Python, is nice and smooth, and in fact has a more consistent feel throughout the pull than does the Python, which (in the one I tried, anyhow) features a discernible change in pull weight partway through the DA trigger travel. I have a Dan Wesson 44 that beats them both in the DA department.
It's interesting to note that S&W made engineering changes to their various models over the years, and referred to them by adding a digit to the model number. This gun is a 66-1; the most recently produced 66s were designated "66-6."