http://www.evastore.jp/pc/index.php?toid=PC_ARTICLE&fromid=PC_ARTICLE_LIST&article_id=23184&category_id=247
and the bottom numbers are colored based upon their respective eva unit:
00 is orange, 01 is purple, 02 is red, 03 (bardiel) is black, 04 is white, and mark 8 is pink
we know 04 is white (well, bright silver) because of this action figure:
SPOILER: Show
but the other numbers on the shirt (5, 6, 7, and 9) aren't left out, and they don't all have the same color either, meaning each color was chosen based upon... something
has this shirt revealed the colors of the four unknown evas, like that action figure did for 04?