Not sure if you got them or not but the part number for the outside roller assy is 6000005883 and the middle ones are 6000005781. The first part number is labeled as R but I believe the only difference is the orientation of the wheel. The outside wheels have a taper, so I think you just need to flip the wheel around to make it work for the L, I've just never personally done it. But I would just find your local Roland dealer and they should be able to get those parts to you, Roland still stocks them.