All 15- and 20-ampere, 125- and 250-volt nonlocking receptacles shall be a listed weather-resistant type.
Not required to be WR if it is a locking receptacle.
406.9(A)....
Unless there is something in 680 that says otherwise, that is how I see it.I have to install a twist lock for a pool motor. I would assume that that would mean the twist lock receptacle would not have to be WR