I looked on the outside of my boxes (seasons 1-4, 7), but I could not tell which, if any, of the sets are widescreen. I netflixed them about a year ago, but I cannot recall. I know they were "widescreened", but the show was not shot that way - at least initially. Are any anamorphic?

They are all anamorphic, and I believe the show was/is shot that way.