Of course it does. It depends on which is "more positive," the alternator or the battery.
If you are stopped, let's say for an extended period, the load comes from the battery to the starter relay and to the headlights
But if you are RUNNING down the road, with an otherwise factory bulkhead connector and ammeter, the power path is ground.......headlights........battery stud.........fuse link........bulkhead.....ammeter.........BACK OUT the bulkhead.........to the ammeter output stud.
The battery is NOT the power source when the alternator "has the load."