Definitely the front calipers have sensors and front brake pads mounted. Rear brake pads will not fit into front calipers using the locking pins and anti rattle springs. I'm sure it can be done, but it would be very hard to put rear pads into front calipers. You would definitely know something was incorrect, and I don't think the pads would remain seated very long. They would probably fall out very quickly. Are you sure the "wear pattern" on your rotors is actually a wear pattern? If you buy the rotors new, the entire surface will sparkle. The rotors on my car have been subjected to the elements in the yard, and the previous rotors had the exact wear pattern.

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1984 300D