Maybe they're for assembly purposes? So the person putting 100 of these on an hour can just set it on and not have to worry about lining up any holes to thread the bolts in?
Something like this is not typically a big deal to us working on our own car, but when you have to put a lot of these on all in a row, it probably saves a few seconds each time and reduces the likelihood of a stripped/cross thread bolt, cut gasket, etc.