It's authentic. He spoke and did a demo at Defcon 17 in Vegas in 2009. I was actually there, but missed his demo because I only attended the iPhone seminars.
He explains the baud rate at 2:06 (if anyone here is interested).
Also, he's been responding in the thread that I originally found the YouTube link in yesterday in case you want to ask him any questions (same user name - phreakmonkey). The video is two years old and someone had reposted it. He probably noticed the site name on the YouTube comments and went there to answer questions.
My first connected computer was a Kaypro 4 which had a built-in 300 baud modem; 1984. Prior to that my first unit, a Commodore 64 was not connected to anything other than its original cassette drive and later its external floppy drive. ... I'm starting to feel old ...
I love it! Although I never had to use an acoustic coupled modem, my first BBS running RBBS ran on a 300 baud modem. We released the first version of the Wildcat! BBS during the 1200 baud era and continued selling it until late 1998 when we sold the BBS product line.
I remember pay something like $150 for my 2400 baud, and it was FAST. Also remember being on the wildcat BBS too. To really bring back some memories, play this on your desktop machine, as I don't think it will play on the iPhones: http://www.aporcupine.com/dialup.swf