We’ve uncovered a sketch in NASA’s own archives, boldly listed online for anyone to see. We think the date to throw the unwitting off the case, however, we know better.
GEORGE MUELLER VERSION OF SKYLAB SKETCH AUGUST 19, 1966.
The online description of the item ties it to Skylab but I think we know better.
http://ntrs.nasa.gov/search.jsp?print=yes&R=MSFC-8886938