1) It depends on your provider. Here our provider, PG&E, puts the 3/4" plug after the meter so that they can hook up a temporary gas tank to your house if they need to shut down the main incoming gas service. As for testing, you need to remove the meter any way to either install the guage or cap the pipe so that you may install a guage at another outlet. 2) A shut off valve after the meter is up to the Administrative Authority. Some cities allow us to put in a shut off and some don't.