No! That slot is for adjusting the headlight beam side to side. What you do to adjust the light to center it (if required) is loosen the bolt just enough to allow the headlight to be moved back or fourth in that slot until the beam hot spot it straight ahead. Then you carefully remove the bulb and tighten the bolt down. Once it's tight you can put the headlight back in. It should never need adjusting to center the beam again. Of course the up/down adjustment knob behind the windshield can be adjusted to compensate for a passenger or loading.
