Really?... Thats interesting. I just had to buy a Russel fitting from summit racing. Only on the inside of the end with the female threads, it didn't have an inverted flare. It was just flat on the inside. So I just used an O-ring, not the most ideal thing but it doesn't leak.
So since you are selling one of these fittings that in fact does have the inverted flare on the female thread side everyone should get their fitting from you. Because summit doesn't sell one that does, or anywhere else for that matter.
On a side note for anyone wondering this fitting will also connect to your factory sending unit and allow you to connect braided line with a female hose end on it. Granted that its -6 AN.
That's unfortunately what I had to do too, but it hasn't caused any problems in over 4 years.