Like Mr. Phillips, I as well am a member at Montclair. Prior to the merger, however, I was a member at Rock Spring.
Rock Spring was organized by a group of ten citizens from West Orange in 1925, many from neighboring Essex County Country Club. While the Club History Book does not go into great detail about the Wilkinson Design, I am assuming that he was an early contact or simply drew up the plans on his own, hoping to land the job. However, one of the founding members, Charles F. Robbins, had a relationship with Seth Raynor. This relationship led to the club having to pay only a small fee for Raynor's design. Thus, Raynor was hired in 1926 to design the golf course.
Unfortunately, the land in the northeast corner of the property was deemed to be too rocky to adequately house a golf course. This land was sold, and land across Walker Road was purchased for the current fourth and fifth holes. Banks carried out the construction, but whether or not he followed Raynor's plans is a mystery to me. This explains the course's current layout.
I hope this helps to shed some light on your question.