About Cargolux and passenger aircraft : In the past, Cargolux used to operate passenger aircraft with their subsidiary "Lion Air".
There were also passenger 747 operated for the Hajj flights to Mecca and for a number of other carriers.
Right now, Cargolux has a fleet of 11 747-400F's, LX-FCV, GCV, ICV (the prototype which was original planned for AF...), KCV, LCV, MCV, NCV, OCV, PCV, RCV and SCV... TCV is due to arrive later this year. Nevertheless several registrations are "recycled". There have been for example several FCV's..... So just because you don't see a Cargolux -100 or -200 nowadays does not mean that it never existed!
For more information check Oli Sigurdsson's page about the CL-44, but also about the aircraft in 30 years of Cargolux service :