For me making an assumption that Fiat keep the codes "close to there chest" is wide of the mark, they will of course keep the engine ECU and all the "breakdown codes" on the dealers computer but as my experience shows all the equipment on the car is not always covered.
Firstly although Fiat central/manufacturing do have the vehicle key and body computer/security codes this information is not kept on a dealers' systems or any Fiat system the dealers have access to.
In general the codes in the UK are kept by RetainaGroup - International Security Register (was NVSR - National Vehicle Security Register) to which dealers have access to but have to pay a fee to retrieve your cars data. This fee is normally transferred you.
I have had the unfortunate experience of trying to get my vehicles security data from the ISR and they would not release it to me regardless of what proof of ownership, birth certificate, my blood, my DNA ...... However they were happy to dive the information to a dealer. The dealer filled in the form complete with my personal identification data, address, bank details and faxed it of to the NVSR. Nothing came back. The dealer chased up a few days later only to find the request form with my personal data WITH the car key, immobiliser, etc codes was faxed back to the wrong number! F*ing brilliant. Now another fax machine/persons have all my personal data, car registration, all security key/codes and of course where the car is normally parked!
This got me so annoyed I went straight to Fiat UK and escalated the whole subject of owners not being able to get their car's data. When they said sorry not allowed for security reasons I said what security. Not only has my cars security data been sent to some fax machine so has all my personal data. Brilliant!
In Europe the customer who buys a new Fiat get the car's Code Card supplied as it quite rightly should be.
Whilst I appreciate the basic security intent and central filing of the security data it should be made available to the vehicle owner up request by the owner. Sadly it was/is NOT and to my knowledge nothing has changed in recent years other than the price goes up.