I'm not sure if they were ever for retail sale. AFAIK they were first made for the women who accompanied their husbands or bosses on Nixon's trip to China in 1972. Since they're stamped with the Great Seal, I don't think Coach could have made them available for retail sale without the government's permission. They may have been made in 2 different sizes but again that's just based on what I've read. Most of the ones I've seen are style 9170, Classic Shoulder Bag/Classic Pouch.
There was a later version made during the Reagan years (1981-89) along with a wallet and checkbook holder, and which MIGHT have been tied in to Nancy Reagan's Say No To Drugs program. My guess is that the Nixon-era bags are the ones with the small black Coach plate, and the Reagan versions often have NYC creeds but no serial numbers.
The Coach Archives has several in their collection. Below is a part of the description posted by an Ebay seller about one of the Nixon-era versions:
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