Any legal citizen have indeed implant to identify themselves. combined with remote readers or with more advanced version by "key press" they create floating hologram that works like 3d QR code. Republic have invested tremendous amount of money for this ID system and its security so forgery even though it's not impossible, it's still very difficult. Moreover All citizen data of each planet is stored to that planent central database and each planet uploads as backup their data to Republics Capital database. The system will also keep log where each persons last logon spot and if abnormalities (one ID found in two different places in timeframe that no human can travel such distance) are found it alerts the police / overseers.
So in order to get working ID you don't just need a functioning ID you also need to create working entry to said database.
Gawa, the leader of Gawa's fist and certain other Bladrons have these IDs Though with mention that they are "legally" working with Bladrons.
Your assumption are very much correct both by the common workforce and their daily comforts.
The main workforce of the planet is either immigrants or lower ranks of the still legal citizen. Also because of annexation the original people of Biitran, Lilidrans are among this standard workforce.
Those who are rich, intelligent or otherwise well doing ones are living in so called Blue Zones. These Blue zones are highest security and wealth areas in the city. In Threm for example Blue Zone is 40km diameter circle at the very center of the City and is separated from Yellow zone by walls, security gates and military operated checkpoints.
At the south corner of this Blue Zone of Threm there is located private owned lot by Gorestian Corporation D&H Holdings. Private lots or corporations (even international) D&H are free to execute their own jurisdiction in their lot as long as it's not contradicting general Gorestian laws. Also Idra security and police forces don't have license or obligation to perform any activity in said places.
On this Bordering Blue-yellow Zone lot stands "Golden Sun" the largest Hotel - Casino - Entertainment Complex that been built. Also because of it's location they are buying, according the rumors, security services from Trumbo. Golden Sun advertises itself with high security both inside and outside. The Complex for example is protected by Force field, missile launchers and other weapons usually found in heavily fortified military bases or planetary bastions.
Next to the complex on the Yellow zone there is campus of Biitran Technical University, also funded by D&H.