Bob
Actually that bunker was still around in 1950. I found an article from 1950 in the Augusta paper where Sarazen was very critical of it.
Kalen
At one time that old 7th had a shared super fairway with the par-4 3rd. Its not shown in the second map but in subsequent maps (and old aerials) the band of rough between the holes is gone.
In July 1937 (OB Keeler) and January 1938 (Bob Harlow & Charles Bartlett) a series of articles explained the changes that were being made by Maxwell.
In the July article Keeler writes that there will be a new tenth green, shoved back and up on the hill. He says the celebrated 5th green, "which hitherto has inspired more convulsive sobs in the 'crying room' because of its originality ridge-pole topography, will be a reasonably spacious carpet, encouraging the bold second shots that are the dream and insignia of the Grade-A golfer." He explains the changes to the 7th (which I posted on the other thread), which was basically cutting of the left hand lobe. He also claims there was a existing bunker behind that green. And then he goes on to talk about the 9th green, which I believe is where RW got his information. He says the green has been re-contoured and bunkering changed to prevent those from playing down the 1st fairway.
The January articles are both very similar. The general theme of both articles: ANGC was originally designed to emulate a British links course (with its bold mounding meant to replicate dunes) but after fours years of competition its clear that was a failed experiment and Maxwell will be converting it into an American course. The changes he has made are a new 10th green and alterations to the greens at #5, #7 and #17. Both article are almost identical in there explanation.
"The abruptness of the dunes contours, which frequently caused well hit approach shorts to kick awry, has been done away with. So also have the peculiar undulations in the ground adjacent to the greens has been reduced, although at no sacrifice to testing a shot.
The greens of the fifth, seventh and seventeenth holes have been rebuilt, and an entirely new tenth green has been cut into the hillside behind and at the left of the original green, on high ground."
There is no mention of any change to the 9th, which may explain why RTJ still showed the boomerang on his map in the late 40s. Both articles mention the principles nose is not going anywhere. Based on this info I'm wondered if Whitten has overstated the changes made by Maxwell. For example it doesn't appear the 7th green was moved.