Ah, hold on, sorry, the Stencil Report doesn't work on the Document Stencil.
However, I have just proved to myself that if the shape in the Document Stencil has been renamed at some time then its Name and NameU will be different, the substitute cannot then find it. Hmmm.
Can you copy the shape from the Document Stencil to a new ordinary stencil, save it. Now run the stencil report and check its Name and NameU.