Anyone know why some Casio international sites seem to be referring to some watches using a slightly different code?

For example Casio Japan refer to the new Men in Smoky Gray Gulfman as the GW-9110GY-1 > http://product-search.casio.jp/wat/g...ge=0&rd=201109 . However some Casio international sites are referrring to it as the GR-9110GY-1 > http://www.casio-intl.com/wat/watch_...110GY-1&n=1409 . A new designation and new caseback? Or simply a typo on Casio's part??