I'm pretty sure this is Final Fantasy 3 (from the original Famicom), not FF6 (from the Super Famicom).
It's doubtful that anyone in Japan would use the mixed-up American numbers, which have even been officially been "straightened out" by Square on the PSX, with FF Anthology and FF Chronicles.
The original FF3 has never been seen in America. NOA apparently specially requested that Square give the original FF3 another shot, after Square decided to bring FF1&2 (the original ones) to the GBA, simply because FF3 has never been available in America before. So I'm guessing that an American release is downright inevitable.
Edit: Here's how the whole "FF naming thing" works, for anyone who's confused.
There were actually THREE Final Fantasy games on the Famicom (the Japanese version of the NES). Nintendo of America brought the first one over. But for reasons that we don't really need to get into right now, neither Square or NOA brought the "real" FF2&3 over to America.
Final Fantasy 4, 5 and 6 were made on the Super Famicom (Japanese SNES). Square brought FF4 over to America, but they decided to change it's name to "Final Fantasy 2". They skipped FF5 entirely, and brought over FF6 as "Final Fantasy 3".
So the games many of you probably remember fondly as "FF2" and FF3" were really FF4 and FF6.
With Final Fantasy 7 on the PlayStation, Square stopped using mixed up numbers. Nowadays, you're only supposed to use the mixed up numbers when you're speaking historically about the actual American SNES cartrige games, and even then it's a good idea to be pretty deliberate about it.
Square ported FF4 to 6 to the PSX, and released them in America, under their original names. This was the first time FF5 became available in America.
Square had intended to make enhanced remakes of the first three FF games for Bandai's Wonderswan handheld (which was more powerful than the NES, but not as powerful as the SNES), but they had some sort of unknown mystery problem with FF3, so they forced a downgraded version of FF4 onto the system in it's place.
Square then decided to re-remake the Wonderswan versions of FF1&2 and put them on the PSX. FF3 was mysteriously skipped. Again. But it was released in the States, which was a first for FF2.
Then more recently, Square decided to bring FF1&2 to the GBA as downgraded remakes of the PSX versions, to take advantage of the "NES Classics" fever over old games on the GBA. FF3 was skipped again. Or so it seemed.