[Scythels]

Correct, a 500mm lens and a 50mm cropped to "500mm" would look the same, provided the entrance pupils are located in the same place (and if you're shooting something at infinity, it'll be close enough that no one can tell). 

 

The aperture will not change perspective, as entrance pupil *location* is important, the size never enters into the geometry until you get into telecentric or hypercentric systems.