It is quite simple to remove your Fiat radio. You will need a set of radio release keys (PC5-83). These are inexpensive and are around £2.00, you can obtain these from Amazon.
Once you have the radio release keys, push them into the 4 holes in each corner of the radio (See image), apply a little pressure and the radio will release from the dashboard. The radios label will be located on the radio's casing.
The Fiat radio serial is 14 digits long for example BP237534082298. In some cases this may start with CM and also be 14 digits long.
The Fiat Continental radio serial is 19 digits long for example A2C9915190300043272.