I'm not aware of them ever actually striking a five dollar version and I don't think the discussions of whether or not they had the authority coiming up until after the one dollar coins were struck. Although I haven't seen it mentioned since then, I do remember that the coins were exhibited somewhere immediately after they came back from their shuttle ride. (But when they were displayed at the ANA they did make the claim that this was the first time they had been publicly exhibited. So either my memory is faulty or the earlier exhibition wasn't considered "public".) As for whether or not they had the authority to produce the gold coin, they actually do. The planchet size is almost the same size as the 1/2 oz gold eagle, and they were planning on making them as 1/2 oz gold coins. The legislation that authorized the AGE back in 1986 allowed the director of the mint to change the design without having to go through Congress.
It is thought that the "Cheerios Dollars" were struck with the same die pair that struck the gold pieces.
