This seems to be a quirk with the way Fords are ordered.
I work at a dealer in Missouri and sometimes I'm in charge of ordering vehicles. When entering codes to add to a vehicle, an available code is a front license plate bracket. This code is automatically added to orders for units going to a state where a front plate is required at no cost. Due to MO requiring front plates, most of our vehicles come in with a bracket and rivets in a plastic bag in the trunk and are installed before delivery. Some specialty vehicles (like the Focus ST and Mustang) we ask the customer before installing them. However, we've only had one Fiesta ST come in so far and as far as I could tell, it has the bracket on from the moment it got off the truck. There was a day between when I first noticed it arriving and when it was prepared for inventory, but I feel like I remember the bracket already being there (which is strange).
We have a couple more Fiesta STs on their way in so I'm going to keep an eye out and see if they're all coming from the factory with a front bracket installed or not.