NC Adoption Law

We are in the very beginning stages of contract signing with an agency and I am sure they will answer my questions but I'm kind of curious now. I had been reading NC law about adoption and it said that TPR doesn't happen until the adoption is finalzed. As I understand it, that can take several months. In most states is TPR signed once the revocation period is up and the attempt to locate birth fathers has expired. In north carolina I think the revocation period is 7 days? So even after that 7 days the birth parents could still change their mind all the way up to TPR? Or am I misunderstanding?