Don't the American versions have a slightly different name.
Not sure about some Asian Countries, but for most of the rest of the world there is just the one version. Seems only North America likes to be different
SGS EyeEye I9100 = UK/International
Samsung Epic 4G Touch = Sprint
AT&T Samsung Galaxy S II SGH-I777 = AT&T
T-Mobile Samsung Galaxy S II SGH-T989 = T-Mobile
AT&T Samsung Galaxy S II Skyrocket SGH-I727 = AT&T
Are the ones I could see on a quick look at xda-developers. This will be the best place to look at when it comes to modding your phone. Make sure you pick the correct one or things will go bad.