Don't think so. Herblock (the Washington Post cartoonist of the day) had fun portraying him as "Neutral Nixon", since he was viewed as something in the way of damaged goods after losing the gubernatorial race in California in '62. My sense is that PA governor William Scranton might well have come away with the GOP nomination. Since he was approximately middle-of-the-road politically, he probably would have reached out to another centrist as a running mate (my memory of who else might have been prominent in the center of the GOP at the time is failing and I'm too lazy to do any research at the moment).