I'd be cautious about swapping sides with the rotors as well. Spokes for lack of a better description of the rotor are set up to resist tension or pull under braking. If mounted on the opposite side they would be subjected to compression under braking. I'm not confident that under sever load or heavy braking that they would behave the same as when placed on the proper side.
Think of it like spokes on a bicycle wheel but remove one set of spokes so they all go the same direction like that of the rotor. In the correct orientation you could pull the tire and the spokes would pull the hub in the same direction without issue. However, if you reversed the wheel direction the spokes would want to flex and bend under pressure instead of pulling the hub. I hope this makes sense.
yep, that's the big question at this point, whether those 'spokes' are active or passive.
My guess is they are passive, they don't deform enough for the direction of force to matter. My logic for thinking this way is why would anyone purposely design a brake rotor that flexes under load, its bad engineering design. If the metal deformed every time you hit the brakes, the rotor spokes could eventually experience metal fatigue from repeated deformation cycles, that wouldn't be good. It would make more sense to over design them such that the rotational load was negligible compared to the strength of the spokes.
But, its just a guess, I could be wrong, and we all know the consequences of rotor failure could be pretty severe.
edit: after a bit more thought, I'm joining the "NO" camp. If it were my bike, I'd be concerned enough about it that I'd be constantly checking for early signs of fatigue/failure. That alone wouldn't make it worth the cost savings of buying the proper side replacement rotor.