I just spent some time studying several aerials of Philmont, North and South courses, from the Dallin collection of Hagley Museum, that cover the period from 1924 (the year the North opened) thru 1939, courtesy of Wayne Morrison.
Based on my suppositions to date, I had fully expected to find a course much different from today, which would lend some credence to the theory that perhaps Flynn came in and made some wholesale changes to the course sometime after it was originally designed in the early 20s, apparently by Park. After seeing the evidence to date, I had no other way of explaining the fact that the club seemed convinced for many years that William Flynn had been in fact been the designer.
However, what I found was only remarkable in the sense of exactly how well preserved the courses are from the time of their inception. Yes, there has been some tree growth, but nothing too restrictive, and some other changes have taken place that I'll outline below, but what struck me most is simply the fact that the courses that Philmont golfers play today are by and large the same courses played by their forebearers and are among the most well-preserved in the Philadelphia region. The North course in particular now seems to be one of the most pure, unadulterated Willie Park Jr. courses in existence.
What has changed over the years? Let's start with the South course.
It's impossible to determine exactly what Park did to the South course that John Reid had created but since 1924, the changes on the South are as follows;
* A driving range had been built in the 50s/60s that destroyed what would have likely been the 3rd, 4th, and 5th holes of the South and the father/son team of Willam and David Gordon built 3 new holes to replace them; today's third, which essentially runs along much of the same corridor as the original 3rd, and then built today's 12th and 13th holes by cutting parallel swaths through the forest up above the par three 11th.
* Sometime between 1924 and 1938 the 18th green was relocated about 60 yards to the left of the original green. The green that was built, in almost an island of sand, still exists today, but its authorship remains unknown. The original bunkerless 18th green looked rather unremarkable contrasted to its replacement.
* Some cross bunkers that affected today's holes 7 & 8 were removed. Sadly, some really cool churchpew bunkering down the right side of 8 has also disappeared over the years, and today's hole is somewhat bland by comparison to the original.
* The creek fronting the 6th green has since been turned into a pond.
Beyond that, the 1924 course is virtually identical to today's.
In the case of the North Course;
Besides the removal of a very few fairway bunkers over the years, and a change on #2 where a pond replaced a diagonal stream crossing in front of the green, and someone's addition of a large fronting bunker on #10 green (all likely done by the Gordons), today's North course is virtually identical to the North course as it existed in 1924.
Interestingly, I doubt the construction was simply a paper job on farmland, because it's clear from the aerials that several holes on the North had to be created by wholesale cutting of trees in forested areas, such as 1, 2, 9, and most of the "upper" holes near the clubhouse. So, it would seem that some degree of sophisticated engineering and landscape management had to be employed in the construction of the course, which could lend credence to the Flynn/Toomey construction team theory.
The bottom line to me is simply that if the Platt letter is correct, and there is absolutely no reason to believe a well-known and well-travelled fellow like Platt would be mistaken, then today's North Course at Philmont is indeed one of the most pure of Willie Park's designs, probably in the world.
In any case, it's a very good course and the club should be extremely proud of their heritage and stewardship over the years.