Did Grandpa Date in the Old Style?

17th and 18th century documents are full of dating that may appear to be “off.” This document was dated Stow, Mass., 23 January 1746: 7.

It’s 1747 in our modern style where the “new year” started on January 1. It’s 1746 in the old style where the new year started in in March. It’s not some other parenthetical notation, an abbreviation, or a stray mark or error.