Bonus question: apart from the "T" both models seem to belong to a related series. What does the "T" mean?
Both of these models are freewheels not cassettes. They are for the most part interchangeable. The only area of concern would be the size of the largest cog. Too large a difference from you original model may necessitate a longer or shorter chain. You may also need to make some small adjustments get the shifting optimized.