Sadly, no, Turnbull; I have never seen it and I believe you're right in that it was never released. I can live with the other scenes not being released on the originals, but I would love for this scene to be, just for the sake of seeing it. I can't see why it was not included.
Mick
PS> I too, noticed Vito's rolling his eyes as he turns away. That whole scene, from them leaving the wedding to visiting Genco also ultimately made Michael's corruption all the more vast.