Carolina Golf Club (in Charlotte - my club) is an interesting example, I think. I'm sure we'll always call it a "Ross course."
It was built in 1929, clearly "by Ross," but original design and construction records are gone (not at the club or in the Ross archives). We do have one small drawing of the course that shows the outlines of the holes and the sequence of play, and an old aerial photo, dates unknown, but obviously early. The course, which started as a daily fee, then in the late 1950s became a private club, never had much money and therefore was little changed until 2008 when Kris Spence was hired to "re-do" the course. The little changes had to do with some greens being tinkered with, two tinkered with a lot, many trees planted (on what had been open dairy farm land), a number of bunkers filled in, and greens contacted substantially in size and rounded (due to mowing patterns, intentional or not). Also, when the course went private in the late 1950s a new clubhouse was built across the property from the old log cabin clubhouse, and as a result the sequence of playing the holes was changed substantially (nothing so simple as reversing the nines).
With the Spence "re-do" here are just some of the things that happened. Two of the original holes were abandoned completely to become a new practice tee area. These were the holes that had become 1 and 2 in the late 1950s. The new, replacement holes are nothing like the old ones, and although are said to have Ross characteristics, are dramatically different from the rest of the course. Another completely new hole was created, a par 3, which is in the same general area as the hole it replaced, but does not overlay the old hole. I think this hole fits in well. Four holes have completely new green locations, two moved back (and one of those to much higher ground), one forward, and one to the left. Again, the changes seem to fit. In at least three cases the outlines of the original greens were obvious, and those greens restored. The greens that had been tinkered with a lot over the years were completely "re-done," but there's no way to tell how they reflect the originals. Spence also added back old bunkers that could be identified. The course was substantially de-treed, though not to the original tree-barren dairy farmland.
The fairways were changed substantially (not the routings, except as noted above). The old fairways had lots of humps and hollows (in some little ways like British links courses), including features which legend has it were originally cow paths from the dairy farm days. Obviously little to no grading was done when the course was built in 1929. Spence did substantial smoothing of the fairways, the humps and hollows and "cow paths" are gone. In addition, ups and downs have been softened. E.g., a number of holes play from high ground through low ground and back to high ground. Steeper ups and downs were graded to be less steep and the low land filled in.
I like the "re-do" very much, particularly as it relates to the greens, bunkers and surrounds. The fairways, not so much. As I said at the outset, we'll always call it a Ross course, but is it?