In theory, you might see small black bars with a 1.85:1 movie on a 16x9 TV, but there are two things that make this unlikely:
1. A lot of 1.85:1 movies are cropped/matted to 1.78:1, and...
2. The overscan on most TVs will prevent you from seeing the black bars.
As far as 1.66:1 movies go...