There is one move that really proves something is wrong - if you do it one way - uke gets dm, if you do it other side - there is no dm at all.

There it is (mod classic):
hold all, contract right pec, raise right shoulder, left-rotating chest and left-bending lumbar, space, lower right shoulder. dm.
now try do the same with changing sides.
failure.

Maybe that's good thing to know, before deciding on your opener's side, btw.