FBA Labels are used to identify items which are set-up/added in Seller or Vendor Central. This means that required data for an Amazon FBA label can be located in your Amazon Account.
Go to Manage inventory to view all products
                                        To get FSNKU column to populate, use the
                                        Preferences: button on the top right of the page
                                    
Once enabled, user should have access to FNSKU, Product Name, and Condition