yes, Rathbone was actually an excellent fencer; interesting trivia from his work in "Court Jester" w/Danny Kaye:
"Basil Rathbone, a world-class fencer called "the best in Hollywood", said that Danny Kaye, who had never fenced before, was as good as he was with only three weeks of practice; Kaye was a natural. "With his quick reflexes and his extraordinary sense of mime, which enabled him to imitate easily anything seen once, Kaye could outfence Rathbone after a few weeks of instruction". [1] In fact, in one scene, Kaye (42 at the time of filming) was so skilled, Rathbone (then 63) could not keep up, and was instead doubled by sword choreographer Ralph Faulkner (which is why the viewers don't see Rathbone's face in that scene).
http://en.wikipedia.org/wiki/The_Court_Jester