The front sight on the Model 66 has been changed. They came with a stainless front sight from the factory.
I thought this initially but now think this sight is original. According to S&W, the SKU for this gun is "102712 M66 357MAG 3”* RSR Special". The other 66/3"ers sold in 1990 had a SKU of "102719 M66 3" RRWO RB Whit Faux Ivory grips".
The RRWO denotes Red Ramp front sight and White Outline rear sight. Since the SKU for my gun does not have this designation, I believe RSR elected a plain, blued front sight. This sight does appear on other S&W revolvers of this era.
I'm happy with it as it is but I wonder if other users feel the red insert is a plus or a minus...