From what I understand, a lot of these guys tinker with their clubs per course & conditions: grinding, bending, tweaking. Even adjusting mid-tournament. If that's the case, I wouldn't think there would/could be such a thing as a "duplicate" set.
That aside, if Tiger knew/believed he didn't have the right club for the shot he was trying to hit, why did he try to hit it? This guy is universally lauded for his mental game, his course management, the move seems very surprising. Especially given how Zach ruled the par 5's while laying up. And it's not like Tiger is a slouch with a wedge in his hand.
Anyway, my 2 cents...