Reservations for shows on Radiance of the Seas?

I have read several threads about reservations for shows on many other ships. The cruise planner for our upcoming Alaskan cruise in June on the Radiance keeps telling me that reservations are not available. But I also don't really see any discussion threads about reservations on the Radiance in general. Is it that the reservation window has not opened up yet or is the Radiance a small enough ship that they don't do reservations for shows?

Thanks in advance for the help!

No reservations on Radiance class ships.

Reservations for shows are only available on Oasis and Quantum class ships. All the other's it's first come first serve....so line up early.