This GB farthing sized item seems to have an obverse from George III (KM602), but a reverse from George II (KM572). Also, it is real thin (about .8 mm). It reminds me of some of the Chinese counterfeits where the obverse and the reverses don't match.
The contemporary forgeries were usually pretty good. I would say this is a poor counterfeit, that date should be George II bust.
