Yes, these are rotary couplers. Here you can see the brake pipe is on the "wrong" side of the draft gear. When these cars are coupled for rotary dump operation, the brake pipe is on the right side of the cars (when viewed from the B end). The brake pipe can be cut in or out at each car from one side of the train and it can remain continuously connected throughout the dump phase. In this photo, two rotary ends are coupled together so the brake pipe crosses underneath the couplers.