I saw this stated in the Disney Magazine when the ride first opened.
I don't debate that it may or may not actually happened (nor do i want to thread hijack) but the naysayers usually point out the differences in the ride mechanisms to describe how it couldn't have actually happened the way it's been reported (differences between the teacups and the pinocchio ride cars...and that the imagineers imagined what the ride would have been like rather than actually doing it).
Many Bothans died to bring MiceChat this information.
I had a freind working in Imagineering at the time and she told me the reason for all the delays was simple math. When they did the blueprints and models everything worked fine - on paper. When the actual boats where built a mistake was made in some calcualtions from blue print to final product, and the boats where too long to make the tight curves. So they had to go back and redo the math, then make all new boats that were smaller in length, then everything worked fine. The only tweaking on the last drop was the control system for the big splash. Once that was ironed out so you got wet but not drowned, the ride was tested, tested again with people and then finally opened. That's it, directly from someone whe was very involved with the ride and went on to be supervisor of the Paris version.