That was my first instinct too, but surely not correct. If they do always pass the smaller piston first then the only difference would be the bleed nipples/crossovers would be the wrong way around. Having it on the front of the wheel will only mean it passes the small then large piston going downwards rather than upwards for the subaru way. Mounting them in the subaru direction wouldn't cause the piston order to change at all, small piston still touches first. Swapping left to right will mean the crossovers/ bleeders are the right way around but the large piston will then touch first.
Same problem the BRZ guys have when putting Subaru Brembo's on their cars, just the other way aroumd