I have a cheap Litex ceiling fan that comes with a short downrod. I need the 36 inch version and Litex doesn't seem to make them. The current downrod is unthreaded. Downrods seem to come in two version: threaded (Westinghouse, Hunter) and unthreaded (Emerson). Do I need the unthreaded version? No one selling Emerson unthreaded seems to ship to an APO address so I'd rather buy the threaded version if it will still work. Are downrods universal? Thanks much for any help you can give.