Unfortunately, it's not a spinner, it's a paddle.  A spinner freely rotates 360 degrees, and is (almost) always an optical device.  A paddle has a limited range-of-motion, and is (almost?) always a potentiometer device.
The NES version of Arkanoid is virtually un-playable past a certain level without that controller, though.  I've never researched it, but I'll bet it's worth buck$ to serious NES collectors in working condition.  
edit:  According to Ebay completed auctions, it's not really that valuable after all.  Bummer.