I don't think that tells you anything about what's in the box; the shipping container is a custom clean room env designed to maximize use of space in a cargo plane.
Harddrives typically come in a vacuum sealed bag, so I wager they could apply the same technique here if the components were small enough.
My point is that the size of the container tells something about the size of the components. "Completely disassembled" would mean every nut and bolt would be taken apart, which I don't think is the case given the size of the container.
Hard drives are not shipped anywhere near a clean room env. The inside of that box is probably one of the cleanest places on earth. It even blows other clean rooms like space craft manufacturing facilities out of the water.
And you're missing the fact that the outside of the box isn't a clean room, and it has to mate with the clean room at the customer facilities. A bajillion baggies of parts is a non starter if the outside of those baggies isn't a clean room env.
