In general – for older models (before 3200/6200) iSCSI license was zero cost but still had to be explicitly ordered. NFS was extra charged. For current models you can select one free protocol license as part of fundamentals package, which means either iSCSI or NFS.
There were (and are) also various bundles which include several licenses.
System comes from factory preinstalled with all licenses ordered for this system so you can see them using “license” command (or in FilerView/System Manager – do not ask me where ☺ )
Or go to http://now.netapp.com/eservice/agree.do?moduleName=PROTOCOL to see all licenses registered (a.k.a. – ordered) for your FAS based on serial number.