That would be great and exactly what I was thinking about not paying to have it graded when it could be a 10 dollar coin. I also didn't know where to begin.
When I first saw the coin, I thought it was a 62D with surface damage but he claims it's a wheat so that theory is out. Generally, if there was a screwup at the mint and the die was damaged or modified, there will be hundreds if not thousands of examples with the same oddity....think D over S varieties or overdates like the '42 over 1 Merc dime. Unique mint errors are usually one-time events caused by debris getting between the die and planchet.
After looking at the photo again closely and looking at a couple of UNC '52D and '62D coins, I tend to agree with you. I think the top part of the 5 was damaged a long time ago where the metal was cut and bent over into the shape of a 6. Being buried under the ground for a long time made the sliver of metal look fused to the surface of the coin. If you look at the top of the 5, it appears to me that there is less metal sticking up from the surface than the other numbers around it. Also, the curve of the "6" has a peaked surface instead of a flat surface like it's neighbors.
