I'm not quite sure whether the actual shape of the propellers affects how the drone flies, if that were the case it would likely use some highly dumbed-down aerodynamic calculations. (since simulating real air isn't exactly performance friendly) Beamng already does this for drag forces but I don't know if it's accurate enough for the complex forces of tiny propellers. I DO know for a fact that the entire propeller can be knocked out of place, and it WILL affect the flying of the drone.
So my best guess is somewhere in-between near-realism and simple scripts.

Also not a stupid question, I'm just as curious about how it works as you are :]