I'm sure it's fine (Corsair undoubtedly filled it full - with a bit of room for expansion), but if you wanna be on the safe side, next time you take the cooler off, you might wanna consider turning the radiator 180 deg (vertically), to keep the intake/outtake ports (oriented on the bottom) on the radiator full of liquid - that way you can be sure the pump never cavities if the rad isn't completely full of liquid...

I’m sure it’s fine though.

Nice case btw! :)