Ed,
I recall that Ross' Inverness had a few holes added for the 1979 PGA and Fazio's work looked nothing like Ross, to the complaints of many. That had the pros complaining and got lots of pub, but I think it was even before that when Brad Klein's Ross designed club up in NE somewhere went through a divisive remodel.
I am moving and don't have Brad's Ross book in front of me, but its in there (I think) and maybe if he sees it he will chime in.
This site has discussed this before, and Tom Doak had another example when this has been discussed back then, but Inverness is where I became aware of the issue as both a golf fan and golf architect.
Later, in 1984, and having moved to Texas, I recall getting beat by Coore Crenshaw for a few club jobs because, well, Ben is legend in Texas, and I was a damn Yankee, but also because they had been pushing that they were "restoration architects" to these clubs.
Not sure when Geoff S started pushing for Thomas restorations (again, would need the date of his books on Thomas, Riv, etc.) but recall them being big items, just not sure of exact dates.
So, as far as my experience, that puts it in the 1977 time frame, and picking up speed by the mid 1980's. As always, I could be wrong. More to Dick's point, it wouldn't be surprising if someone pushed to restore some Old Tom Morris golf course to his original design shortly after his death, as a "tribute" (albeit, with a few pence changing hands!)