Visually, in the mist primitive the vertical stroke doesn't pass through the middle of the character, while in the car one it does. Besides that, their stroke orders are different.
Another question (near end of RTK1 beginning RTK3)
DETACHO 離す MICHAEL JACKSON 林檎 Are they the same radical?
That depends on what you're calling "Michael Jackson". Just for reference, if it's the top hat + villain + belt + elbow, Heisig calls it sheik in book 3; with the umbrella on top of it, it becomes fowl.