You better check your owners manual before you assume there is a phono stage built into your receiver. But anyway you'll know for sure when you plug it in. With no preamp you'll get crap out...
Perhaps a dumb question...
What exactly does a phono preamp do? Remove noise? Clear up dynamics? What is the purpose? I've noticed even my school's relatively cheap listening rooms uses a very basic phono preamp, I'm just interested in what exactly the effect of it is that makes it worth spending money?