water problems also 78 450slc

have water leaking somewhere in front firewall because both side floor pans are wet especially driver's side.
question?
removed air vent covers from bottom of windshield and looked in
both sides on the fender wall has holes in it with rust aroud it
are these drainage holes or are they where the water is coming in.
ran water in holes but no leaks i could find. the car is sitting and not yet complete restoration so i don't see how it can be coming from the floor boards.
any help?