Jim,
I don't read it that way, truly. It's a compound sentence, and I think they are two separate thoughts, the first being that "they..had our Committee as their guests at the National", AND secondly, "their advice and suggestions as to the lay-out of the East course were of the greatest help and value".
In fact, I think he's expanding and accentuating a bit on the previous sentence where he wrote that they "advised as to our plans".
Now, if he wrote, "they...had our Committee as their guests at the National WHERE their advice and suggestions as to the lay-out of the East course were of the greatest help and value", then I would agree with you.
"There were unusual and interesting features connected with the beginnings of these two courses which should not be forgotten. First of all, they were both “Homemade”. When it was known that we must give up the old course, a “Special Committee on New Golf Grounds”—composed of the late Frederick L. Baily. S.T. Bodine, E.C. Felton, H.G. Lloyd, and Robert Lesley, Chairman, chose the site; and a “Special Committee” DESIGNED and BUILT the two courses without the help of a golf architect. Those two good and kindly sportsmen, Charles B. MacDonald and H.J. Whigam, the men who conceived the idea of and designed the National Links at Southampton, both ex-amateur champions and the latter a Scot who had learned his golf at Prestwick—twice came to Haverford, first to go over the ground and later to consider and advise about our plans . They also had our committee as their guests at the National and their advice and suggestions as to the lay-out of the East Course were of the greatest help and value. Except for this, the entire responsibility for the DESIGN and CONSTRUCTION of the two courses rests upon the special Construction Committee, composed of R.S. Francis, R.E. Griscom, H.G. Lloyd. Dr. Harry Toulmin, and the late Hugh I. Wilson, Chairman."