It is the only original component in the system.
BTW, the calipers have "L" and "R" cast right into them in case you have problems with such things. I guess if you really did know the cars then you would also know that the brake hoses wouldn't install either @Sheik Ya Bootie
Still looking for an intelligent response on ABS bleeding.
Every time you make something idiot proof, along comes a better idiot.