That's just letter coding.
You could get other-region data to work with GT3, by changing the region code with a hex editor. That's how I, and many other people, got to play GT3 with miles & mph as opposed to the European kilometres & km/h.
Since the PS3 is region-free for gaming... I can't see any particular reason why not. But then the thought would also occur as to why they couldn't do a simultaneous worldwide release if all of the copies of the game were the same, but with different languages...
The answer? Only PD can say.