No they didn't.
http://forum.square-enix.com/ffxi/th...Version-Update
A new graphics stabilization option has been added to the Etc. tab of the FINAL FANTASY XI Config program.
Not even a mention that it's for GeForce 600 series or anything until days later when got a little bit of info: http://forum.square-enix.com/ffxi/th...457#post387457
That's all I know has ever been said about it.

My point is, to quote what you said earlier:
It is not something you should be using unless you've been expereincing black screens/freezes/that sort of thing.
Why not? Does it change graphical quality? Affect performance? If not, why is it something you have to turn on at all instead of something permanently implemented?