I have tried like hex screws in single coils before but not the traditional slotted screws. The ones I tried used ceramic bar magnets though too. Then there are p90s but those probably aren't what you mean.
Traditional fender style singles use rod magnets as poles themselves while pickups with screws for poles will often have a bar magnet of some kind underneath, so the poles/screws are made of some other material. So the design would way different from the ground up and it would hard to attribute any particular difference to the poles/screws specifically.