I have one too and, while I noticed it was different, I didn't think much of it.
Actually, I thought it was a better design to allow for the antenna to be "rotated" on its base for better aesthetics (it seemed to 'click' as I rotated it).
Mine had a natural curve that I was able to rotate to follow the rake of the windshield. The base seemed to allow for that adjustment.
I think I might like that better (or I'm trying to validate my decision) than the completely vertical antenna (no disrespect to others who have that version). It makes it almost disappear... to me, at least.
I'll post a pic later if anyone cares to look.