Vanilla is a product of Lussumo:
Documentation and Support.
We have 1-6 and 8, and then the Final Five. Where's 7?I don't think Leoben's number has ever been stated.
It just strikes me as odd -- presuming the models were made in some kind of order -- that the "regular" skinjob Cylons weren't numbered sequentially.Maybe they're named in order of rank or significance.
I don't think Leoben's number has ever been stated.

I was not alive for the first Battlestar Galactica
but it's worth noting that the original series featured nightmare fodder like this.
Would Tigh or Adama not recognise either 6 or Starbuck as a younger Ellen.