The model number doesn't help because every radio has an individual code. (If it didn't there wouldn't be much point in having a code anyway). Assuming that it's the original radio that was fitted when the car was manufactured, any Ford dealer can find the code for you. When I worked for one, a few years ago, the charge was £15.
Alternatively you can get the code online but to do so you'll need the serial number of the radio, which means being able to remove it from its mounting. There are several firms offering the service. This one seems to be well-reviewed:
http://www.radio-code.co.uk/