Lighter, from your Original Post - "Whichever door was selected, Monty (who knew where the car was) would open one of the remaining two doors to reveal a goat.

Yes, it is fundamental to the problem that Monty knows where the car is and makes an informed choice to open a door to reveal a goat. This gives you information (in the form of a probablity, not a certainty) about what is behind the door he chose not to open.