You have that reversed. The correct term for the finish of the early 3-5-7 isNice gun.
One point: That is a Dual Tone finish. Duotone was the aluminum / black / blue finish found on the first Scout .22 single action revolvers.
Splendid examples! Number 19 and a nickel as well! Do you recall the acquisition history on either?
I noticed your 6” blued has very dark stocks too.