Sven,
Intersting take, but I would consider CGC a classic era golf course because of its 1922 renovations, and a pre-golden age era course in its original form. As Mark asked initially, just what is a classic course? Merion was changed from 1910 to hosting the Open in 1916 and the Amateur in 1930 (I think) Pinehurst was altered almost continuously, but by Ross. So, if done early, when do we consider a course still taking initial form, and when do we say its final form? Luckily there is no huge fight to be had in varying answers.