Let me first re-iterate that if something is working for you, I wouldn't rock the boat. It's not worth it.
Also, my endo doesn't like generic, either, and the first thing he did was take me off generic and put me on Levoxyl, same dose as the generic I'd been on. My labs 4 weeks after that were WORSE than they'd been on generic.
However, I think that anything SOLD, not manufactured, in the U.S.