Accessing the rear master cylinder is a booger -- it's worse on the '88-'89, IMHO. but yes, unless you want to try the rebuild without pulling the unit out, you're pretty much gonna need to pull down the exhaust (the chamber too depending on year).
It's easy enough to figure for yourself -- follow the pushrod and clevis off of your pedal, and the hose down from the reservoir, then see what you can touch/see with all the exhaust left in place. Not a good story, but it will let you decide that the books are correct (or not).