Existence of a subgame perfect Nash-equilibrium
The following proposition is well known: 


  If a stage game $G$ has a unique Nash equilibrium, then for any finite $T$, the repeated game $G(T)$ has a unique subgame perfect equilibrium outcome in which the Nash equilibrium of $G$ is played in every stage.


Since your stage game has a unique NE of $(T,R)$, this must be the outcome of the SPE of any finitely repeated game based on this stage game. Specifically regarding your question, it is impossible for $(B,L)$ to be played (in any stage including the first) in any SPE of the $T$-times repeated game.