Yes, they say TSL. TSL is a trademark of Interco, the maker of the Super Swamper. It stands for Three Stage Lug and is on nearly all or all Super Swamper tires.
Your tires are LTB's, but they have the TSL technology like most other swampers. I think you'll enjoy the tires, although they wear a bit quick on the road due to the softer rubber compound.
I've got TSL Radials and the TSL/SX myself, keeping the Radials for onroad mostly.