All golf courses change, even as we discuss here. In the minutes (or seconds) since you found this thread and clicked, subtle changes have occurred to every course you ever stepped foot upon — from wind, erosion and all sorts of natural causes. They may be subtle and minute — but they are changes. Over time, they mean less depth, more depth, filled-in holes, more holes, dead trees, more trees, wash-outs, rivlets, etc.
I always ask the question on restoration — to what year, month and minute would you like the course "restored"? Of course, there is no answer. We can only restore to a particular time, and that is what "we" — in the present — feel is right and proper. Look at Chicago GC...it's Seth Raynor and the 1930s. Is that OK? I think so, but it;s not Chicago GC from the 1920s or earlier.