William III Crown - Thoughts please

[Ætheling]

I was about to put this on eBay, just assuming it was a bog standard worn 1696 crown. So I photographed it, looking at the photos and the coins I thought oh it's a 1698, looked in the coin book and then though, wait hang on there ain't a 1698. So I've looked at this coin every which way, in natural light, artificial light and thought hard 'the last digit is a 6', but as worn as the coin is, it certainly looks more like an 8 - however, looking at 1698 halfcrowns the 8 is a different shape to what I have here, it looks like a 6 which turns at the top and comes back to make an 8. I can't find any evidence of any overdates for these 1696 crowns, which was my next logical thought. The edge date is OCTAVO as per 1696.

The coin weighs 28.5g and is very worn. Silver ring when dropped and it travels down a magnetic silver slide as one would expect silver to. I though perhaps a forgery was the next logical conclusion.