That's definitely not a true-trac, unless they changed the design. From what I remember, you can see the worm gears through the diff case on the true-trac.
The True-Trac is a worm-gear based traction-sensing differential. It instantly senses when one wheel loses traction and simultaneously transfers torque to the opposite wheel. There is no slipping to cause heat and wear like in a standard clutch-based limited slip differential, but engagement is smooth, unlike a standard locker. Basically, it acts like an open diff until you break traction.