Rick Morgan provided the following with respect to the A3D-2T Skywarrior external pylons discussed here: http://tailspintopics.blogspot.com/2013/09/ta-3b-skywarrior.html. (Rick also provided pictures of TA-3Bs with the pylon and practice bomb dispenser that I've added to that post.)
Concerning pylons on A3Ds, as I understand it all of the Versions had
hardpoints to attach them. This is a photo of a VQ-2 EA-3B in the Med refueling from a VA-216 A-4B
off Saratoga in 1967 with what I believe is an ALQ-31 pod installed.
old VQ friend tells me that they actually flew fighter training missions during
this period with the equipment due to the lack of other EW assets in 6th
fleet, most of the other aircraft being in Vietnam. This is the
only time I’ve found so far where EA-3Bs were actually used for active jamming.
(Contrary to a lot of published references, I have yet to find a VQ operator
who used the EA-3B for jamming in Vietnam- the stories undoubtedly confuse the
EAs for EKAs).
The ERA-3Bs at VAQ-33/34 carried ALQ-76
pods on their pylons, of course.
For a brief description and a picture of the ERA-3B (and an explanation of A-3 Bombers versus Versions), see http://tailspintopics.blogspot.com/2010/09/mighty-skywarrior.html