Reversing the Lines (L1-L2) by swapping sides would not matter. Same for swapping Load terminals.
Only when swapping one Line input and one Load output (or both) across respective In's and Out's, will trouble begin.
By this, I mean to:
[*]Place Line "A" on one "Input" terminal, and Load "B" on the other "Input" terminal,
[*]Placing both Lines "A" and "B" on the "Output" terminals and the "Loads" on the "Input" terminals.
...along with any other possible variations of the above.
This would create a malfunction as leaving a live circuit on the load side after the device has tripped from a ground fault.
Don't know of any damaging effects to the device(s)...only to the personnel!