Yes it is backward compatable and will work with whatever interlocks are avalable for your particular model. In your case it will work the same as the a Pro-S revolving back.
I maybe sticking my neck out here, but I think with the exception of the lenses for the SD model, all the parts are interchangable. That is the viewfinders, screens and backs. I think the lenses can be made to fit with an adapter. Some of the parts will also work with the RZ too. (But check with someone that really knows.) Ric.