This is less sure, but the Atlantis
from "Conspiracy" might have been an Excelsior
-class Starship. This is based on the fact that a diagram of this class appeared in the mission orders for this ship. Well, anyway, this ship had a registry of NCC-72007. So, it's possible that Starfleet was still making these ships as late as the 2360s.
DS9 had the opportunity, when they switched to CGI, to create new ship classes for the battle sequences. Instead, they simply created new models out of the existing models and added a few designs from ILM. So, there must have been a reason, other than budget, that the producers decided to reuse the old models.