Definitely not a 2001. That's definitely an older Whelen without so much as a doubt in my mind. The tone is distinctively old Whelen. Also note the wind down and how it cuts off. And actually, after the old Whelen and the T-Bolt (wow...it does sound a wee bit sickly) shut off, you can hear a newer Whelen going in the background.
According to her MySpace profile, the recorder of the video, "Abby," lives in Florissant, MO, which is in St. Louis County. That verifies it as a Whelen, but this also is super interesting to me because I had absolutely no idea there were 1000Ts in St. Louis County. I thought they were all 1000s. Very cool!