99% sure you have a KGII, only because I found one this summer in similar condition:
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On the back you can see the rounded outline of Lady Britannia's shield (see my farthing, below). Mine is bent, and worn to hell, but if you tilt it back and forth you can see the outline of King George II much better.
It's bittersweet for me, because this is *probably* my oldest coin, but with the date worn off it's impossible to say. It competes with a 1749 British Farthing I found in the same yard, a week or two earlier:
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In any case, congrats! So cool to hold an old Colonial copper that made the journey across the ocean so many centuries ago.