Yeah, IIRC, it didn't contain any "unseen" footage - just scenes taken straight from already commercially released videos.
I recall Mark Davis saying in an interview that he had gotten girls to do foreskin play in quite a few scenes but those parts were often edited out.
Vivid were seemingly one of the more foreskin-afraid studios. Sometimes an actor would not be fully erect at the start of a sex-scene, especially if it was one with lots of "acting" beforehand. If the guy was circ'd, you'd see the girl work him up to stiffness but, if his glans was covered by foreskin, you'd see a brief exposure from mid-distance and then cut straight to a fully-erect cock.
Nicole Sheridan & Voodoo shot a lot of their own stuff after they hooked up which I assume gave them more creative control over the finished product, even if it was distributed through Vivid. I don't remember but the scene you mentioned might have been from before then. You can usually tell - if there was a separate cameraman, it's prob from early on, because on their own shoots, Voodoo, and sometimes Nicole, would operate the camera.
