as part of their new applications in training, they did not have the resources to supply these types of equipment to their team. So the supply guys went to purchase the necessary equipment through diving retailers including this example and issued to their men. Rich also mentioned that he remembers they were issued later on as wide-scale in the military until the mid-70's he believes, which makes me think it could possibly be the TR-900 that he is referring to. He also said they also supplied him with a Rolex Submariner but he lost it during a training routine to the ocean since it had the very flimsy bracelet instead of the nato strap and it broke. Another reason why these straps are much more purposeful in the military than bracelets 
Best,
Jon