Actually mine's different from the reference too. Mine's one of the GBAtemp-branded ones, and I'm pretty sure it's legit since I've been using it for ages and it works with all the special homebrew and blah blah blah.
The layout of the numbers on the Actel chip itself is the same type that y0's has (not the layout Catboy's has).
As for the numbers, mine are later than Catboy's, but earlier than y0's... this seems to indicate Catboy got an earlier one, mine was later than his, and y0's is a recent batch.
EDIT: Better pic...
http://i48.tinypic.com/2ephawh.jpg