Did you do the 29er conversion yourself? The dropouts are indeed extended compared to the original fork.
Coincidentally the very first 29er fork was a modified Fournales as well. In the early stages when Gary Fisher was experimenting around with 29er wheels, there were no suspension forks available for those wheels, and regular telescopic forks were too difficult to modify, so he chose the extended legs Fournales fork to use it for the prototype frames. I've also seen a modified Fournales with custom extra wide linkages adapted to fit Fatbike tires. (again before Fatbike forks were widely available).