Hi @Carter41,

The easiest way I know to do this is to run an admin Provisioning Report, selecting the Courses and the "include deleted items" options.  You'll get a CSV file you can open in excel and search for the SIS_Id.  You should then be able to get the course ID so you can restore the course and remove the SIS_id from it if you wish so it can be used elsewhere.

Hope this helps!

-Chris