i was wondering how
Will it return everything thats in view, just stuff on the specific part, or will it return everything
on the specified layer that is in the component assembly under the specified part?
Since you are calling it on a specific part, it should return objects from that part. I would not expect it to screen or filter objects that are outside of the current view or blanked. I would just expect it to return anything in the part that is on the specified layer.
There is a note in the docs that says "The part must be the displayed part."