If your boxes are metal on the surface and you use RS covers and self grounding receptacle outlets you do not need to use the jumper to the box from the receptacle outlet, but I still do it anyway even if it isn't required.
I was unaware that there were RS covers and boxes that were listed for grounding.
It may sound like a quibble but 250.46 B only applies to flush boxes. I can understand the position that the self grounding receptacles would be sufficient to ground the RS cover if the receptacles grounding terminal is bonded to the Equipment Grounding Conductor (EGC) but to say that pathway is adequate for the box via the cover is not within the language of the code.
250.146 Connecting Receptacle Grounding Terminal to Box.
An equipment bonding jumper shall be used to connect the grounding terminal of a grounding-type receptacle to a grounded box unless grounded as in 250.146(A) through (D).
(A) Surface Mounted Box. Where the box is mounted on the surface, direct metal-to-metal contact between the device yoke and the box shall be permitted to ground the receptacle to the box. This provision shall not apply to cover-mounted receptacles unless the box and cover combination are listed as providing satisfactory ground continuity between the box and the receptacle.
(B) Contact Devices or Yokes. Contact devices or yokes designed and listed for the purpose shall be permitted in conjunction with the supporting screws to establish the grounding circuit between the device yoke and flush-type boxes.