It's ironic that the presentation era of ANGC I would pick would be one for which I don't have a wealth of graphic or descriptive evidence.
I think I would pick 1946 - the year before RTJ lined up and then executed a vision for the course.
While I would still have to give up elements of strict purity - the original 10th green, the original 7th green, the principal's nose on 11, the starker geometric outlines of #4 green and the earliest presentation of #9's complex - I imagine the mid 40s had the last vestiges of rough hewn shag, open treeless ground game, and certainly the old 16th, which I bet was a fun little gimmicky pitch not unlike playing the 12th from halfway between 11 green and the current 12 tee.
I suppose, that given the deprivations of the WW II era and the club's earlier financial difficulties, it was the last time Augusta, though already tinkered, was still innocent and not so aware of itself as more than "Bob's retreat."
In so saying, I have no problem with the trim and self-aware presentation RTJ originated architecturally there, though it is the real leakage of Mackenzie and Jones' collaboration and the time when Augusta became more like we know it, than it was in concept and physical origin. Those values have contributed to the necessary evolutions of GCA as much as they have had a desultory effect on principles, only recently re-championed.
I do not like that technology, proprietary hegemony and mass tournament spectacle has permitted the course to present itself radically different from one season to the next, but I don't play it and in some way I know the reaction to those artificial values causes real working architects to do it better on the courses I might play.
So for me it would probably be the 1945-47 era of the course, the course just came from being used for livestock grazing, still had the Mackenzian touch in its bunkering, contour and camouflage, still was rough around immensely broad edges and the first era of tinkering had a decade to settle in.
cheers
vk