The CEM Bilevels in Toronto are absolutely beautiful. You guys will love these cars.
My two cents on the D4500s:
Back in 2005 when MCI updated their D-Series, there was the "05" model, Contemporary model (CT), and Classic model (CL). The CT model took some of the features of the 05 model: flush-mounted windows and newer headlights. The CL model remained largely the same. As a kind of unwritten convention D coaches with flush-mounted windows and newer headlights were designated with CT on the wiki. For operators who continued with the old headlights and traditional windows, their buses were designated with CL. As far as I can tell, MCI only used the CT and CL designations on their website and other promotional material. The badge next to the door on the coaches still just read D4000 and D4500 as did their builder's plate/sticker. So in short, the wiki just identifies a CT or CL coach based on the headlights and window just for differentiation\categorization sake.