Let's not forget that Jack didn't favor the EB-3 for long. He said so. In later years he chose an EB-1 when he could have easily gotten another EB-3.
Then there's Crobot bass guitarist Jake Figueroa, who was given a '62 EB-0 that "was actually a prototype." Maybe they could have found a bassist who knows something about the history of the model.
Early 70ies? Jack's Warwick phase no doubt. He played the real early ones.
Yes, Jack was playing Warwick before Hans-Peter Wilfer even imagined it.