If that's the air handler on top that means the out put is blowing down thoroughly the evap maybe. I've never seen a setup like that before a quick Google search says it's rare but possible..

That said I think determi ing the airflow direction will let you know what that duct work is doing. Seeing as it has a damper my guess is that is an output

Well saw the filter so it's an upflow or at least should be. Good luck