In both cases, the left-hand side looks upside-down but the right-hand side looks right-way-up, as if the writer has rotated the page to always write on the rig

In both cases, the left-hand side looks upside-down but the right-hand side looks right-way-up, as if the writer has rotated the page to always write on the right-hand page. Seems likely they are right-handed, then (or, this comes from right-handed practices).