Of course that is the case an elac is an elac.
but....
What fredgrav was saying is that not all elacs are the same.
The onboard software can be different and intermixabilty can change
Can be one way interchangeable or 2 way.
I think elac 1 and 2 must have the same OBRM fitted but never assume.Airbus compatibility and interchangeability can be quite complex.
I know some operators dont like swapping known U/S components into another slot lest damage be done.Especially very expensive items like flt ctl boxes.
Worth considering before you do a quick swap.
The U/S elac could be taken out because of what it talks to / damaged wiring etc and therefore placing a good one will render you U/S with 2 stuffed elacs.