And consider that if it is the RD, then a new Ultegra RD-R8000 ss or gs is only about 70 to $80 USD. You can also use a 11 speed 105 series RD which will be even less money. 5800 series if you can find it will probably be the least expensive NOS. But even the RD-R7000 series is almost half the price at $45 USD.