Not sure about that, but in them days they had the labour do do all the walls, unlike today. Some men built, some shaped stones, some filled in, and some brought stone to site. All using stone brought up by ploughing, and quarrying on site.
I've seen some amazing walls, some very vertical ones. Some parts of the country they erected shelters over the walls, like a tunnel, and worked all weather's.
The styles differ in just a few miles some places depending on stone. Lake district is lovely flat stuff, Yorkshire dales, big lumps of limestone.
Hardy men back then, day in, day out, all weather