dumb question. on the back of the cartridge where it has the Nintendo molding... does it have the Nintendo molding?
I own a few Reproduction carts and its either the way you took the pic or the plastic looks awfully close to that of a reproduction cart. the repro carts I own have that same sort of slightly bluish plastic look to them. they are just slightly off color. essentially they just look less aged, not damaged just like the plastic has less time in the air.
EDIT:
Its also completely missing the cartridge designation... the NTSC numbers.. should be something like SNS-RI-USA and under that should be "made in japan". I understand this might be a different regioned cart but it should still have some sort of designation like that on it for any market.