With over 6 billion people in the world; we are not even sure that no 2 fingerprints or irises are so much alike they would be seen as the same; and you would be able to differentiate 2 users by the way they are typing or acting with the environment.
Not only this, but your overall mood; the fact if you drank too much coffee, did not get enough sleep, are exited and a bunch of other variables could lead to other patterns.
For people speaking two or more languages fluently; it is even shown that when you speak another language it alters the active regions in your brain. So if for example you chat in French, you might invoke other patterns in your typing and world interaction.
But indeed, if a pattern is error-less, it would show up.
Compare it with a drum computer. People offset the beat with a few milliseconds because otherwise it sounds to sterile and clean. Perfection is actually not the most beautiful thing to listen too.
So yes, it might be possible to identify a bot; but it cannot by a long stretch be used to tell apart different users.