So far we have been told that none of the humanoid Cylons are copies of actual people/colonials, and that the 12 models were supposed to match 12 human archetypes. (The latter was said long ago and may not be valid.)

However, it is indeed unresolved if the Final Five have always had the same form in every incarnation the way that the 7 younger Cylons do. It does allow some interesting plots if they don’t, in which case the final Cylon (or for that matter Tyrol, Anders and Foster) could have been other people who died before those bodies were born/created.

So this is an interesting one, and it does create a “holy shit” moment.