It has been my experience that you will be able to fire OK without the plugs
in the peep holes at that temperature. They are usually left out to begin
with anyway, in order to vent the kiln at lower temperatures, and then put in
as the temperature rises. I normally put the plugs in -- except for the top
one which I always leave open -- when I turn the kiln to high. But I believe
you will be all right to fire without them to cone 04.
at a high school in Georgia