If you change the ecu on a fiat punto do you need to match it with the key?

hello my friend (im not stupid enough to have a fiat) has been having problems with her punto the revs are eratic.....she took it to a small garage and they told her the ecu was faulty ...she said it had 40 fault codes..anyway ..if i was to change ecu with one from a breakers ..would i need to set it up with the key ...or any other ideas would be helpfull