Directional rotors?

[cencalal]

I'm looking for a good used Brembo front rotor on ebay, and seeing lefts and rights, but checking part numbers shows left and right are the same.
In this case it's an 848 SBK 320mm that I need for a project.  Some rotors have a stamped direction arrow on the carrier, even though the two rotors of a pair are identical, symmetrical, and show no slanted or inclined features.  Is there anything to this? 

Thanks

[Duck-Stew]

Some rotors are universal fitment.  Some are designed to only be left or right side.  If they are designed for directional, then you really can't use them in the other direction.

[cencalal]

Maybe i didn't make my question clear.  If the Brembo rotors spec'd for a Ducati 848 look identical, and the left and right have the same part number, why is there a directional arrow stamped on the carrier?  Does it matter?  I'm doing a single disc setup on the left, and there are some clean used rotors for sale that came off the right side.  Is it because once they've been used in one direction it's better to keep them in the same orientation?

[Speeddog]

These rotors are directional:

https://www.ebay.com/itm/EB108-2013-DUCATI-848-SUPERBIKE-EVO-RH-RIGHT-FRONT-BRAKE-ROTOR-/292049678747

Some OEM stuff is, some is not.

[Duck-Stew]

If the rotors have been ran a particular direction, then the rotor to button and button to carrier contact areas have been bedded in for that one direction due to the braking forces applied during its life.

I'm not sure if you could use it in the opposite direction and get good life out of it.  Perhaps yes as the contact areas haven't been bedded in for the new direction of rotation.