Ira:
Colt and Ross did not work at Old Elm "around the same time." They worked on it together, at the same time, during Colt's second North American visit in April and May 1913. Ross is often cited as doing the bunkering, but Colt laid out the location and major design features of the bunkering and Ross supervised. So Ross was actually on-site during construction, something Colt was not. Ross also worked with Colt as an "associate" (per local newspaper accounts) during Colt's third and last visit to NA in 1914. This was at The CC of Detroit. Colt added length to his 1911 design in 1913; and in 1914 revised bunkering and added length for the 1915 US Amateur. Ross is credited with on-site review of all of Colt's bunkering changes in 1914 to confirm the master's design was followed. I can't put Ross on-site at CCD during Colt's 1913 visit, just 1914. But clearly Ross had a part of at least two Colt designs.
Just btw The CCD is one of the few courses in North America of Colt's where he actually saw some version of the final design, both in 1913 and 1914.
Anthony