im gonna say fake for the following reasons, on comparing with my box (and some of my others):

all versions of these boxes (US/UK) have commemorative series plastered on the fron of the box.

it doesnt have the choking hazard warning on the top right of the box like mine

it doesnt have the little Registered mark next to the S in FORMERS, or next to DECEPTICON in the yellow on the bottom left

it doent have the TM mark next to the decepticon insignia and skywarps name on the bottom left

also, various TMs and registered marks are missing on the inside of the box

George