Tested this. It didn't work in Office 2003 well.
by R. Proffitt - 11/8/12 12:59 PM
In Reply to: How do I convert a .docx fill-in-the-blanks form to a .doc? by N.T.Gray
I had to unlock the document to type into the fields. If you need to do this, you'll want Word 2003 and dig up the old discussions about fill in the blank documents.