I'd suggest it is Factory built in Thailand. My 2016 'S' was delivered pretty much straight away when it docked in November - no chance at all of going through the Portbury line.
I would also say the changes, although to an extent are 'plug & play' with software upgrades, they are more of a factory job due to stringent requirements for these type of items (very rare for any safety item to be retrofitted or applied at source of market).