The pin that holds the extractor in place is staked on the bottom/inside of the slide. Wouldn't want that pin to start moving downward while you were shooting the pistol. That's the spot closest to the ejection port in the slide.
The second one, more to rear serves no purpose and may be a boo boo.
My P01 Omega has a small burr on the corner of the center section of the slide, like the OPs pistol, but not nearly as big/rough as his appears to be.