Looks like they bought some more land to the south in order to put house lots along the east and north perimeter, and also buying enough to add lots around the three new holes to the south. Not sure who did it, not sure when. But not an uncommon practice, to both get lots for members, and/or make a profit if the club was struggling.
Might have been as early as 1925-9, at the height of the roaring 20's and before the depression, or even after WWII. Probably not in the depression, but then, with courses like PD and Southern Hills being built in that era, maybe Topeka was doing okay and taking advantage of depressed land prices. Speculation, so if anyone knows, it would be interesting information......
Also, looks like they got rid of many short holes on the back nine, which they probably didn't like, and got a bigger maintenance area out of the new plan as well.
Given the lack of irrigation on the NW corner, which was the original 2nd, my guess is they use that as an informal practice area now.