If I recall correctly, a devkit comes with a limited license key (1 year?) for Unity 3D. That was the case for DK1.
Q: I received a Unity Pro Trial code with my purchase of the original Oculus Rift Development Kit. Will I receive another code after my purchase of Oculus Rift Development Kit 2?
A: There are no plans to offer a Unity Pro Trial code with Oculus Rift Development Kit 2 purchases at this time.