Since laser printers all encode metadata into the printed image, and handwriting is unique to the writer, I was wondering if a typewriter would provide a more anonymous form of paper communication.

I expect it would be possible to determine the model of typewriter, but would it be possible to tell if two samples were made on the very same machine? Are electric typewriters better or worse than manual? (assuming the same operator) What about Selectric or Wheelwriter – would frequently swapping out the typing element help?