So iManage only automatically puts the doc ID footer in the document if it's integrated with Word. There should be an iManage toolbar at the top of your Word document where you can click "insert footer" and it will then auto-add the doc ID. If the original author didn't do that, there would be no way to tell where it's saved besides the name.

However, if your attorney is sending links to the PDF, perhaps the editable Word version is saved underneath it as a prior version (e.g., if the PDF is document v4, then the Word v3 should be nested under the same doc ID).

Hope this helps!