foof,
Au contraire! Due to room interactions, it's also a good idea to calibrate a stereo-only speaker setup, as the left speaker can sound slightly louder than the right (and vice versa) depending on distance from side walls, furniture arrangement, etc.
On equipment without level asjustement circuitry, you will have to rely on the balance knob (or slider). Just remember that the slider adjusts both speakers at the same time, so if your left speaker reads 1db louder than the right, you'll have to use a minute adjustment.
