Brake Drum Hub Assembly Mystery

The swedging could be for a few reasons:
- balancing. Some hubs have holes or a cut out section in the flange, so correct positioning would be important
- so the drum does not come off with the wheel

I am not 100% sure, but I think the drums are bought from brake companies such as Lockheed, Wagner, Bendix, Kelsey-Hayes etc. If so, that would explain why are some are swedged & some are not.