The only difference you need to account for is going to be for the beam pattern - specifically the "step". I know that in the US, the beam pattern is stepped lower on the left side so that oncoming drivers are not blinded as much by the direct light. That's becasue we drive on the right.

I guess if you drive on the left with a RHD car, then the beam pattern will be exactly opposite. So if you were to swap headlamps from car to car, you will be more prone to blinding oncoming drivers.