As you approach the ONI doors, turn to the left at the top of the stairs. There's an electronic billboard (i.e. a sign) above a door which is lit with red light.
In my earlier play on Mombasa Streets, this sign was for Huciv. When I exited back to the main menu and then resumed my campaign, it was still Huciv. There was no district banner next to the door.
From the main menu, I started a new campaign at Uplift Reserve on Easy and played through it to get back to Mombasa Streets. I then went to District 10 and the Huciv sign had changed to a WST sign. In addition, the D10 banner was present to the left of the door (see crappy camera image, attached).
In this mode (post Uplift Reserve), the ONI Doors are locked. I don't know if there are multiple versions of the texture mapping for this district or if it's truly random when you begin the mission... but clearly you can get different signs here under different conditions.