I would imagine any two computers at Tesla have a very good chance of having identical normal.dot, and font can be determined by looking at the letter. For a letter, who is using tabs for anything but the start of paragraphs? Even if it's not perfect, it's unlikely to change the size of a word document (which is likely <25 kB to begin with) by a full kilobyte.

Basically all it would tell you is the number of word documents with approximately the same amount of text were printed, plus or minus about a paragraph. Letters aren't frequently printed and the contents of the leak would almost certainly limit the number of suspects to a small handful of people. It's not hard at all to believe that in a group of ~50 people and a time window of ~1 week you might only have one even close match.