Not necessarily. If you have a regulated 12 volt supply and three volts of IR drop on your power wires... does the camera work at 9 volts? Since the manufacturers can't tell you, maybe an unregulated supply that floats up higher than the target voltage would work better.

Not that I'd use an unregulated power supply... I'd rather learn that the camera won't work with that amount of voltage drop, and then have to fix it, than use an unregulated supply. See, if the regulated supply didn't work, then I'd learn some things that, as said, the camera company couldn't tell me.