You are talking L2 version before prelude open beta that size is 0,5GB right
But you should know that are other clients like Alpha/Closed Beta: Client that had only warrios , diferent maps , tows , weapons , giant orcs , diferent user interface played by 400 coreans and 50 devs only
For example i think this is version of prelude that you talking
School of dark arts
But we see mages so is not alpha beta:
http://www.ffxionline.com/forums/attachments/video-games/7980d1060027954-lineage-ii-beta-screenshots-de11.jpg
And we do not see diferent map textures:
http://www.ffxionline.com/forums/attachments/video-games/7907d1059880055-lineage-ii-beta-screenshots-froggy.jpg
We see how dark elf run:
http://www.ffxionline.com/forums/attachments/video-games/7520d1058739069-lineage-ii-beta-screenshots-nicearrow.jpg
Sauce:
http://www.ffxionline.com/forums/video-games/11463-lineage-ii-beta-screenshots-5.html
So tell me if the screens that i sent you are related with client you looking we can go to all those 2003 forums and try contact those people maybe someone still having client. But for now ill proced to explain show Alpha beta stuff