Far too much complexity to be for assembly line only...not like the little trhow away clips assembly lines use are they? These keep the drum positively located on the shoes...note that nothing else in the assembly keeps the drum from moving to some degree about the centerpoint...just too much wasted engineering for unneeded parts...though I do think running without them, under normal conditions and with everything in good shape is ok...might wear the shoes a little uneven and/or faster, otherwise, probably not very noticeable.
brute4c