Your assumption is correct ... and it is even more ephemeral since it also depends on the page dimensions.   The 8-1/2x11 paper that’s common in USA, versus the A4-or-whatever page in Europe, and so on ... your default margins ... even font size.   OLE is going to be necessary here ... or ...

What about Visual Basic or VBA?   Seriously:   it’s built-in to Word anyway, and it can instantiate a Word.Document object, and ... heck, it even has regexes buried in there someplace.   Maybe it could (“if I on-ly had a brai-i-in...”)   ;-)   do the first-step of finding words and page numbers, writing that to a file for consumption by more-intelligent beings.