Colonial Dice: King George III?

[phogan87]

I’ve had these dice tucked away in my collection for about a decade now. Based on the material, the patina, the wear, and the stamp itself I have always given into the notion that they were authentic, however, I thought I would post this photo and see if anybody new enough to either agree or disagree with this assumption. Any help would be greatly appreciated! (The second image was digitally manipulated so that the stamp could be seen better)