Well, not the caliper, but the position of it. It usually means a custom bracket of some kind
Now that you said it, come to think of it, 2JR shaved the caliper for the rear set up. I don’t take off the rears very often, and with this corona nonsense, haven’t been on the track for awhile, so - completely slipped my mind.
Also, even though I have to replace the Wilwood rotors 3x in 2 years, I’m still on the original WW rear rotors, that after 4 years and 70k miles. Only had to change the pads once.
Goes to show that you don’t really NEED to have BBK in the rear, as most of the breaking is done upfront.