That was my impression too - pulling strings doesn’t easily change the time sequence of pilot training. The only question is when the rounds of pilot training started, and whether he skipped a line-up there, but considering it took several months to start, probably was the normal sequence.
And I suppose it says something of the quality of training and how well he learned, that how many years later he could still land on a carrier. (I wonder if he ever did so in training?)
An aside: the military doesn’t give you anything for free. If they give you extensive training for a particular goal, they’re going to want you to obligate extra service time to “pay” for it.
He was a glorified passenger. It was a publicity stunt. He was “co-pilot” in the same sense as a 4-year-old invited into the cockpit to sit in the seat might have been back in the day when you could still do that sort of thing.