Sebastian Horacio “La Promesa” Papeschi and Sampson Lewkowicz Leon Gavilan and Sampson Lewkowicz Sampson Lewkowicz of Sampson Boxing (along with Tello Box), proudly announces a pair of significant co-promotional signings, as super middleweight contender Sebastian Horacio “La Promesa” Papeschi (18-3, 6 KOs) and undefeated super welterweight prospect Leon Gavilan (5-0,