In USN colors, the SEAD or "Iron Hand" mission was supposed to be flown by any attack aircraft in the Carrier Air Wing. The only dedicated SEAD sub variant of an attack aircraft that I am aware of is the A-6B, which had additional electronics and Standard ARM capability. As stated above the EA-6A & B were more for escort for EW jamming purposes with a secondary ARM role than for use as true "weasels". Remember that jamming enemy air defense radars also affects the ARM homing capability due to operating on the same frequencies.