Quite a few early 66 4" no-dashes were modified by their owners with a RR installation to correct what was considered a poor sight picture, especially by many LE agencies. It was an easy modification for a good gunsmith and could be accomplished to look much like a factory original.

A tell-tale sign was a slightly different color red material than was commonly seen on original red ramps, or slightly different dimensions compared to the normal factory size cut on the blade.

I'm certainly no authority on the subject of what S&W has made, but when I see a configuration that differs significantly from the norm, like a red ramp on an early no-dash 66 without having a black rear sight included, I'm a bit skeptical about its factory originality... I would certainly suggest a factory letter to confirm its history if I felt it was important.

In any event, a Mod. 66, especially the P&R guns, are among the favorites in my collection. You're going to love this gun, Fenderskirt66. I believe you'll find a lot of people feel the same way about theirs.....

JMHO