Its odd that Enterprise's registry has been reused so often. The US Navy has a lineage of Enterprises and they're CV-6, CVN-65, and (the future) CVN-80 NOT CV-6, CV-6-A, CV-6-B.
"Canon is only important to certain people because they have to cling to their knowledge of the minutiae. Open your mind! Be a Star Trek fan and open your mind and say, 'Where does Star Trek want to take me now'." - Leonard Nimoy