'E' means 'English', and is part of the serial-# of the universal international language version NGCD games, usually called 'US' versions. They were released in all countries except Japan. Take a look at the epilepsy warning pages (the orange colored ones), they are printed in English, Spanish, French and German to be compatible to all regions.
Edit: No, *both* regional versions originally came with spine cards. For ex. my 'US' Last Blade has a spine card, but it's also one of the later (1998 - 99) international language version NGCD games that has no 'E' in the serial no... quite confusing, but hey, that's SNK... wink
<small>[ January 24, 2003, 12:08 PM: Message edited by: Takumaji ]</small>