How to verify an oracle database license
Anybody can download and install oracle software without any installation codes being necessary. So in effect an Oracle licence is simply an entry in their Licence Management Services (LMS) database. Depending upon what you buy you will get a CSI number. In working with Oracle for more than 15 years this is all I have ever seen at customer sites: a piece of paper with a description of the licence(s), the total number bought and a CSI number. One way to verify your licence would be to create an account on their support site (support.oracle.com) and add your CSI to this account. Then when you log in you can see which products are associated with this CSI. An alternative would be to do as Threaten suggests and simply email LMS and they will send you a list of what they think you own. For the amount of money you pay for an 11gDB licence I would expect something more substantial but unfortunately a sheet of plain text is all you get.