Welcome aboard, King! Have you checked out this book on the KC-135 and its variants? You may want to drop a note to the author, Bob Hoskins (his e-mail is on the "author" page). He's a good guy - we flew KC-135s together at Grissom AFB 20-odd years ago, and he's covered the various -135 models in his book. I don't have my copy at hand to see what it has on Rivet Ball, but I remember that he goes into extensive detail on most of the -135 mods. If you do get in touch with him, tell him Moose from Grissom sent you!
ETA: Apparently, Bob is a model builder (which I never realized before). Checking the list of his other published work, he wrote an article on building the AMT/ERTL RC-135V Rivet Joint for the IPMS Journal in 1994.
