Like modoversus mentioned, they were recouped inventory that was repackaged for sale. Some of the clamshells might differ (I think there were 2 made, with minor differences on the front lower "windows"). The carts themselves will probably be a mix of European and North American SKUs, for the same games, with variances in the sticker art and / or the presence of ERSB ratings badges. (Metal Slug 1st and 2nd Missions are easy examples of the regional sticker differences). The cart sticker will also have unique SKUS that tell you which region it was made for as well, in the upper left. The carts also might have the "patent pending" stamp on the back but that largely depends on when the game was developed and manufactured/printed.
I think that's pretty much it though? Each blister pack probably has some pretty wild variance even if 1 pack had the same titles as another.
