FLO also designed the property of Mountain Lake. He was instrumental in convincing Raynor to take on the job for the golf course. From "MOUNTAIN LAKE" - 'By may of 1915, Olmstead had completed sufficient work to produce a blueprint of the residential park, including blockand lot delineations, all major roadways and the area layout for an 18-hole course.'
So it isn't so new to have a GCA given an 'area' to fit a course in on. I know that this might have been one of the first such, and not as normal at the time as it is now.