You can use regular bolts, but as I said the self extractors are left hand threads. So, you cannot use a dust cap. And you would need a left-handed thread crank remover. These are expensive and hard to find these days. I did remove my self extractors and used these campy bolts so I didn't need a dust cap. And I bought a C-record (left hand thread) extractor. They were reasonably priced back in the day.
Here is an ebay listing for a left hand thread Campy C-Record extractor. My opinion: he's asking too much.
https://www.ebay.com/itm/28406126255...iABEgIqUPD_BwE