Is it Greenstar and AutoTrac ready?  If so, putting a JD screen and globe on the roof (if not already installed) will make it super easy for bean harvest if you have any beans. You can also do Rowsense if your corn head has feelers or they can be installed so it steers for you in corn. 

Or did a previous owner switch it over to Ag Leader monitoring and steering for example? It's best to just try and match what's on the machine already