Looks good to me.
It is a late imitation (100-50 BC) of the greek Massalia Drachms, made by
celtic tribes in the
Gallia Cisalpina (today northern
Italy). The
style and the low weight of the coin points to the late examples of that
type, 2.21g for your coin is ok and within the range.
Style is also ok, so far as I can see from the pics there is no doubt about the genuiness of the example.
Cataloge references: Castellin 1009-1035,
Dembski 115-127
Look here for an (early) example:
http://www.forumancientcoins.com/board/index.php?topic=85564.msg533653#msg533653Regards