No, but they are (usually) meant to be representative of the real thing, to the degree that it's recognizable. The more that representation diverges from reality, the more suspension of disbelief you'll bust for people that see it. Sometimes it can't be helped, or is one of a few things you are expected to take for granted for the plot, and that's generally okay with most people. Worse is when there's no real reason for it to be wrong except for lack of care. That's when it's really annoying.