Omega Calibre 3861 – Single Wheel Co Axial?

I saw in an interview with the great Roger Smith that he noticed that a Speedmaster he owned had a one wheel co-axial escapement, the calibre in question was the 3861. I can’t fine anything to support this? I even asked Omega and they denied, saying that the only producer of a one wheel escapement was Roger Smith himself.

does anyone have one to prove such statement?

the interview was from 2023 with Watch Gecko, in front of a live audience.