I think you’re just confused. 24fps has really just always been used as shorthand for 23.976 fps. 24fps was decided on as the frame rate of motion pictures in the early days because it is the smallest amount of fps you can have and still achieve the illusion fluid motion. You have to understand that film is a mechanical process, and it was near impossible for them to achieve TRUE 24fps in the early days and they eventually figured out that what the cameras were actually shooting was 23.976fps. But the frame rate stuck due to aesthetic and tradition, even when it got to a point where we COULD accurately shoot true 24fps. Even today, the standard frame rate for theatrical films both digital and film is 23.976. It came from tradition; it would be kind of odd if that was just a random decimal someone decided to use for the hell of it, right? Now, you could screen any 23.976fps motion picture at true 24fps and not really notice any difference, but I promise (at least in the case of Star Wars, but majority of others as well) it is more accurate to screen at 23.976, since that is what the cameras captured and the projectors projected. (My source for this info is four years of film school and three years of industry experience, which you may or may not find more reliable than Wikipedia)

But long story short, if you ever hear anyone in the industry say “24fps” what they mean is “23.976”. They are used interchangeably and very seldom is anything shot at TRUE 24fps.