Actually, it would appear that the rear calipers do differ. They have an extra lug for mounting the socket for the wear indicators.
If rear pad wear reaches the contacts is the ASR then disabled? Or do the rears have indicators simply because there is the possibility of increased rear pad wear with ASR actuation?

good questions. Don't know for sure, however I would think your first question might be correct. Mercedes was beginning to bring more automation into the picture around that time frame.

OK, found more information on what exactly, ASC does for the car. It appears the brakes may play a more active role when the car over-accelerates causing possible fish tailing. I don't believe this car has the kind of power to worry about fish tailing, but then I'm not a mercedes engineer, either.

https://www.mercedes-benz-bus.com/en_GB/models/tourismo-rhd/safety/safe-driving.html

As said, only 1 listed for each side of mine and it has ASR. I would expect the EPC to list the options but no.

RayH