Sven,
It does appear that at least some of today's Rock Creek Park GC contains vestiges (including at least one hole) from the 1904 version as recounted in "The Nature Faker" by Wayne Morrison and Tom Paul who recount below;
In his August 24, 1924 Washington Post column, From Tee to Green, Henry Litchfield
West wrote of the planned expansion of the Rock Creek Park golf course,
“Fully twenty years ago Col. Jay J. Morrow, then engineer commissioner of the
District, and the writer endeavored to introduce a public golf course in the District and
a portion of Rock Creek park north of the Military road was selected as a site. The
work clearing the fairways was done by the chain gang and street sweepings were used
for fertilizer, no money being available for labor or supplies. The project finally fell
through because Congress looked with disfavor upon golfing as a recreation at public
expense. That was twenty years ago and golf was not the popular, universal sport it is
today."
"A curious thing has now happened. In planning an additional nine holes for the
public course in Rock Creek Park, there has been discovered one of the tees
constructed twenty years ago and it is to be utilized. It is found in the woods, north of
the Military Road and the flight of time is illustrated by the fact that two trees have
grown up in the center of the tee. The hole as then laid out by a couple of enthusiastic
amateur golfers has met with the approval of William Flynn, the architect of the
proposed addition to the course, and will be completed according to the original idea.
The hole is a short one, a tee shot across a hollow to a green on the side of a hill
opposite the tee."
"The discovery of the old tee and the decision to make use of it proves the truth of the
old adage that time at last makes all things even.”