One clue: the folks whose work I'm looking at have not replaced normal.dot/dotm for months; the change happened somewhere else. They do generate a companyname.dot/dotm and an uninstall-companyname.dot/dotm file with each new installation.
Another clue: another unsolved problem -- sporadic changes in the style of some part of the output from one day/version to the next that aren't intended, and show up as failures because those are the only difference between the new output and the 'golden' doc it's being compared to.
I'm here trying to formulate a smart enough question about this, as I've been away from Word for quite a few years.
I have found this since I first asked above:
"... two basic types of options that you can define in Word. These options are as follows:
• Options that affect the way that the program operates. (The information for this kind of option is generally stored in the Microsoft Windows registry.)
• Options that affect the formatting or the appearance of one or more documents. (The information for this kind of option is stored in templates or documents.)...."
http://support.microsoft.com/kb/822005
Main locations of Word settings in the Windows Registry ....."
(Oh dear lord and little fishes, I didn't want to know that. It might be part of the smart question.)