Patrick;
Hope you're enjoying the long winter somewhere warm.
Now, back to business...
Are we talking 10% manufactured, 20%, 50%, 100%?
It would seem to me that #8 at NGLA is about 20-30% man-made. The rest of it, as Tom Paul points out, is pretty much just what originally existed it seems to me, particularly the mid-body of the hole.
I think that contrasts greatly with many wholly manufactured modern designs, where not a stone is left unturned (so to speak) during the construction process, and the resulting hole or course is completely reshaped by the architect.
In some cases, that has turned out some excellent work such as Whistling Straits, Kiawah Ocean, Twisted Dune, and even courses like Lido and Indian Creek in years past.
However, in more cases than not, I'd argue that most wholly manufactured courses tend to come apart at the seams around the edges. I'll give you an example of what I mean by that...
There is a course near the Delaware shore called Bear Trap Dunes, and it's a very decent, fun course by Rick Jacobson. The theme is "dunes", and large lakes were dug on the property and the sand based soil that was uncovered was used to create faux dunes of various heights throughout the property. It gives the course (on VERY flat original land) some degree of roll and "motion", although too often it's only used as mounds paralleling fairways and greens.
However, once one gets to the holes along the boundary of the property, the whole illusion is lost. All one has to do is look at what adjoins the course and it's flat, flat, flat soybean fields, with nary a foot of elevation change. The contrast is almost humorous, and certainly any notion of a golf course in harmony with its environment suddenly vanishes.