If your steps with NPM were Evaluation of product and then SL something license was bought, you can list your unmonitored interfaces by using SQL query: select InterfaceName from dbo.Interfaces where LastSync < '2014-02-12 09:00:00'. It can be used in Report writer in Custom table with Advanced DataBase Query -> SQL. In other cases Pavel is right.
Beware LastSync date should be less than actual date/time minus few hours and you should not have any manually unmanaged interfaces.