In a keynote speech, Richard "Dickie" George, former technical director for the NSA Information Assurance Director, flat out denied it claiming that they were non-deterministically generated random numbers[1]. He also talked a little bit about how Dual EC became a public standard to begin with[2]. If you have the time, I think the whole video is worth a watch - he goes into the history of DES, espionage between the US and Soviets, getting cryptographic equipment working in tanks, etc...

[1] http://vimeo.com/97891042 (jump to 57:53)

[2] Same video, jump to 30:14