IIRC the military have their own standard on the hook loaders, so any bins would have to be made bespoke for the wagon. Most of their wagons have heavier than standard chassis and bodies, so less payload. Years ago, there was a myth about “maintained to military standards” which was just that, and I’ve seen selloffs that wouldn’t pass a civilian MOT. If you did happen to pick up a bargain at the auctions, it was usually one that had been in the Reserve stock, and nowadays they don’t carry that much reserve stock, so it’s going to have seen some work.