the pads, calipers, and mounting brackets are identical between the 11.25" and 12" front systems. the difference is the steering knuckle. the 12" knuckle has the bracket mounting holes 3/8" farther out.
there are some factory 15" wheels that fit the 12" brakes. the fitment issue is the shape of the rear of the barrel section.
a barrel that has a step close to the mount surface fits 12" rotors, a barrel that tapers all the way in hits the calipers. 15s that is, 16s are big enough.
both are 15 x 7 . the black has the shape that fits over 12" brakes.
I have no idea which shape the Alcoas' are.