Take this for what it's worth:
As stated earlier, my Gen 3 G19 has never malfunctioned, but does spit brass to the face on occasion. The extractor that came with the gun is the LCI with the dip, with a "2" on the post. I ordered a new extractor, still an LCI with the dip, but this one has a "3" printed on the post. I tried the new extractor with 100 rounds of WWB, and while there were still no malfunctions, the brass to the face continued. The old extractor would drop free when doing a detail strip, while the new one had to be shaken out.
I took an Arkansas stone and some oil and rubbed the flat sides of the new extractor lightly in circular motions on both sides. This took some of the black off of the part but not much. After finishing, the sides of the extractor were very smooth, and it would drop freely from the silde with no effort.
After 100 more rounds of WWB today, every round ejected to the right and slightly back (3:30 - 4:00) in, dare I say it, a neat little pile.
I'm not sure what the difference between the "2" and "3" on the extractors mean, or if that has anything to do with it, but I'm happy.