No, that's pretty rare really.. If a pitcher is right handed, they usually feel more comfortable batting on the right-hand side (in relation from looking at the batter from the pitching mound). From this "right hand side," their right hand is doing more of directing the pathway of the bat. It's pretty rare to have an athlete who throws with one hand and bats on the other side.
One of the other reasons it's rare to have a right handed pitcher bat left handed or vice versa is that batting from the other side exposes your pitching arm and hand directly to the pitcher. If you get hit by a 90- mph fastball it will hit your throwing side. That's definitely not a good thing when you are making several million dollars to pitch.