Now the big question is - do they install something for the Semi? A "mega-charger"? I've always thought that V3 was really intended to kill 2 birds with 1 stone. The main cabinet is 1 MW which supports either 4x 250 kW car chargers or 1x large semi charger (and you could have plugs for both, but only operate the system in one "mode" at a time).
My guess is that they might do this at Fremont, as more of a demonstration, but in general Megachargers and superchargers will be separate.
When Elon spoke at the megacharger launch, he said they would guarantee a particular cents per mile for "fuel" for the semi. To me that suggested that Tesla, for each semi customer, would build the charging infrastructure based on their use case (that being - at-base charging, megacharging, all backed up by Tesla solar and batteries) - only by building the entire lot could Tesla guarantee the cost.
In reality each customer wouldn't have a "dedicated" megacharger but customer demands would decide the initial deployment.
Of course this is just my speculation.