Yes.
I prefer to power up camera temporarily during install, so i can gauge if it is installed properly by looking at LCD screen or phone screen if it have wifi.
Still before this you have to angle the lens to sort of the right place, gauging sideways alignment i use the bottom of the A pillars i can usually see in the footage, and also the front of the dashboard.
Up and down dont bother me as you can always adjust that when the camera are properly installed.
Once aimed i slide camera off the mount and press the mount on firmly, then i do the rest of the install stuff, and then finally connect it all to the again mounted camera.
For cleaning, and you need to do that often as a dashcam owner, i prefer to slide the cameras off the mount, usually letting them dangle in the wires draped over my mirror, this way less of a chance getting stuff on the camera lens which if not removed most often sit very close to the glass.