If you’ve never watched “NCIS,” you may be surprised by this bit of casting. But for us fans, it’s perfect: The dry, quick-witted Bob Newhart appears on “NCIS” tonight playing Ducky’s predecessor in the dead bodies department. “NCIS” is a drama, but it was a surprising number of funny moments, and I can’t wait to see Newhart go toe-to-toe (funnybone to funnybone?) with Mark Harmon’s droll Gibbs. Click on to watch NCIS season 8 episode 12 online.