hmm the copper color is exactly in the middle of the rim, I think it fine. I have come across one or two of these type of rims when I was more into collecting.
OK ever time I look at this thing it seems wrong. more info: The coin weighs 10.7 G compared to a normal 1/2 dollar on my scale of 11.2 G. Its 29.58 mm compared to 30.58 mm on the diameter with my caliper. 2.03 mm thick on the rim compared to 2.15 mm. If the edge was worn down on a normal coin this much there would be no reeds.
That info you gave there definitely is intriguing. It doesn't really look to be shaved down by someone. So I really am not sure what to say. Hopefully someone can fill in.