reply to Paralel
Re: Use current ATT Modem for Uverse & avoid New Modem charge? Yup: Totally legit/authentic/current modem.
The question really boils down to "can you avoid being required to purchase what would be an unnecessary modem/can you avoid having to pay that unnecessary $100."
@Thinkdiff's experience is option 2. While not as user friendly (and way more cumbersome for both parties) as this rare instance of BYOD/no charge, it is an acceptable alternative.
If it actually works that way...