Not sure which one is "blown".? But all four ceramic feedthroughs shown in the pic are .001 uf/350V rated.
But.....your HV line (+650VDC) is missing where the unused hole is.? Is this what you were referring to?? If so, there is no feedthrough capacitor at that point.? A wire carrying the B+ high voltage to the PA tubes passes through a piece of friction fit plastic insulation.? You will have to make your own - shouldn't be too hard.? All 4 line transmitters are the same in this?regard.