Tom MacWood:
Actually I had never seen your post-Bell picture of the Duel Hole before. I've seen the other pictures on this page, and I've seen Bell's bunker to the right on one of the aerial photos we have been working from.
The current version of the hole is a cross between the two. The club had us put back the Bell bunker at the right front of the green last year, so it's not in the picture Kalen posted, but it IS there now and looks pretty close to your picture. [Up until now, I had been hesitant to put that bunker back ... because I knew that it had come and gone, and because that has historically been a wet area subject to erosion in El Nino years as there is a LOT of water coming toward the green down #8 fairway.] The current bunkers on the left are different, more like Tillinghast's version, as we have not really worked on those.
The Duel hole has been a particularly difficult one to work on because it's been changed so many times. Someone completely flattened the green sometime between 1940 and 1970, perhaps after a flood event; then Sandy Tatum "restored" the green in the 1970's using the behind-the-green photo that Rick posted, but probably with a bit less contour than the original. Naturally, nobody has wanted me to freelance new contours onto the green, so we've kept it pretty much as-is when we had to rebuild it.
In general, though, the bunkers we have restored are based on the aerial photo taken a few years after Billy Bell's work. To the best of my knowledge, Bell did not alter the locations of bunkers tremendously, but it's tough to say with certainty since there is no aerial photograph of the course from before his work was done.