Chris,
Thanks for checking in on this. I looked at the videos again, and I do think some fw corridors are close to natural, that he routed them in the valleys, and perhaps just softened some of the rolls.
Holes like 12 and 13 are probably pretty close to natural grade, as the natural mounds to the sides are much lower. 17 may be a mix of both, because the mounds do seem naturally lower on the left.
I think if you look at the 5th hole, and you see large dunes left and right, and a flat fw, probably reduced in cross slope to hold balls on the fw (and from last fall, I still trickled off right) and it seems clear to me he sent those horses in a pretty straight line to make that hole playable, and didn't really consider that grading to be artwork. Is is possible that someone had the idea that this w (and maybe a few others) needed some leveling after the fact?
I have told the story before, but when I routed a new nine holes for them in 1985 (and looking at that video, that land looks even sharper than where they built the course) I discussed the 12th green with the committee, which shouldn't be changed, but on the other hand, probably could be, as some members were complaining about it's severity. So, we called Press, and asked him about it, and after some silence, replied something to the effect that we could bulldoze it, because he never liked that green.
Just a great course, and hearing the gca's focusing so much on the greens in that video, I started thinking it would be interesting to focus on the rest!