No that is not correct. The thing is that the accelerometers can not "see" when rotate the IMU along yaw. So it will not make a difference if you just rotate the sensor. Remember that it measures acceleration, which I use to measure Earth gravitational force to calculate the angle. You can also use a accelerometer in for example a rocket to measure the acceleration of the rocket.
I am not sure that I understand your second question? 
- Lauszus