It's known the first handful of CDi titles were re-released into Europe (although it's unknown the exact count). These re-releases most often start with 600 or 699 - instead of the US releases which start with 310690 commonly. However there are more than a few 310690 releases for sale out of Europe in distinctly European-style cases, further clouding the issue.
Additionally I noticed another mention-worthy instance. Same re-release serial, however the case is different AND there's a space in the middle of the serial for the western-style case.
The extent of variants and re-releases for CDi's are not well documented, but perhaps the above clue can add to the pool of information regarding the subject.
