R & D most likely ran several different distributors before determining which worked best for their application and then to the higher ups to negotiate contracts. Some offerings were losers (hemi's) and I doubt they put in anything else but what worked best.
It was not uncommon for owners to replace factory with mallory's. Some v8 mallory's had 4 lobe shafts running two sets of points (each set "sparking" 4 plugs). This greatly increasing the amount
energy stored by the condenser to be delivered to the plugs.