Variation In Rim Height On 1911 Gold Sovereign.

Hello everyone! I'm new here, and have recently bought a 1911 George V soveriegn from a reputable dealer. Whilst handling it, I noticed that the rims' height varies quite a bit, especially on the 'head' side. I measured the rim with digital calipers to be 1.84mm (0.0725") near George's eyebrows, and only 1.49mm (0.0585") near the back of his neck. I read that the mean thickness of a sovereign is supposed to be 1.52mm, so I expected the rim to be thicker. The diameter is very accurate however. Is this unusual? Has it been unevenly struck/milled?

I did a little research on the tell-tale signs of forgeries, and couldn't find anything about rim-height variations.

Can any of you chaps shed some light on this?

Thanks in advance,

-Tone