Second Tommy's sentiment, definitely misleading, but not surprising, you see this all the time. I imagine clubs, or someone in a position of power or influence, seeks to boost the profile or pedigree of their course by tying it in with other, more well known courses (Philmont, anyone?) As I recall from when I worked there in 2003-2004, Art Hills redesigned the Gold in full at some point in time, and was retained by the Club as the Consulting architect for the Gold Course. This may still be the case, but I am not fully certain.
The [Congressional] Gold course incorporates a portion of the original holes from the Emmet routing and 9 holes that were added by George Fazio at some point, probably between 1970 and 1979, across Persimmon Tree Rd.
FWIW, today's Gold Course holes of 1,2,3,4 (fairway),5 and 15,16,17 and part of 18 were originally part of Emmet's routing.
Historicaerials.com shows these additional holes in the 1979 aerial, but not the 1970 aerial, so they were obviously built during this decade, assuming the date of the aerials is correct.