I think there's actually wiring in the harness to do this, but all the bikes I've seen have single filament bulb sockets in the rear signals, no provision for marker lamps. You can swap around socket units if you can find ones that fit, I suppose, and have rear markers. Here in Ontario you can only have red tail lights though... probably not enforced but certain members of the constabulary love to stop bikes for any "offence" so I like to follow the rules.