Ben Kay reports from Inside The Writers Room With Mad Men panel:

Interestingly, the tiny chat I had with Robert Towne involved me asking if he had really been one of the writers on Bonnie and Clyde. He told me he had. Is his name on the credits? No. Did he get paid? Yes. Did he get pee'd off and cry in the corner? No, he wrote Chinatown. Write Chinatown.