Actually my answer was probably confusing when you asked if it was stored as "film" - anything that was shot to film in the first place should be stored on a DVD as progressive, either at 23.976 fps for NTSC or 25 fps for PAL.
But NTSC framerate is actually 29.97 -- 23.976 fps is called "NTSC - film" and 3:2 pulldown is used to display at 29.97 fps. So you could say if the 3:2 pulldown flag is present, then the material is stored as "film".