I see that there is some variation in requirements from place to place.
Some places would consider a receptacle as a possible source of a spark. Others would not worry.
Some places would measure from the regulator, while some rules speak of the entire assembly.
And, of course, requirements have changed over time. For example, Reno, Nv., used to require the gas meter and the electric meter to be clustered together today there is a separation requirement. This detail can greatly complicate service changes.
Isn't it amazing how utilities have no problem posting their standards on the internet for free access- while the NFPA screams that no codes are possible unless they have a legal monopoly? Hmmm .... but I wander
