It is counter stamped, so most likely it is a coin. You shoulda had a size reference like a penny or nickel in the pic. If it is a farthing, I'd suspect it would be a KG3 or 4. I think the majority of counter stamping occurred between the late 1700s to 1857 when the monetary system devalued foreign coins. A US nickel is 21.2mm whilst the farthing was 22mm.
So you hit that early 1700s house? Nice. I didn't get out of work early on any day last week. Prob should have as this week seems like bad weather. Oh well.