It's a typo - might it be '1692' - I don't know that much about Inigo Jones. There is a grooved, carved, stone in Bolton, which is also recumbent and was, I suppose, formerly upright. It's not had any bits chipped off though. The hollowed out trenches are rough, like those on the Devil's Arrows, and not polished in any way. I found it in 2001!