In common with moulds and wheel types the way windows were shown on the models also changed over time. However due to variations amongst different airline liveries and a gradual changeover between types it is difficult to talk with accuracy over specific types and when they were introduced. Below are the general trends in window design in order.
SCHUCO STYLE WINDOWS
A small number of DC10 models were completed with old Schuco style cockpit windows. These may have even been leftover Schuco stock.
BLACK OR WHITE WINDOWS
In the 1980 and early 90s windows were usually black. Where there was a dark cheatline they were often white and sometimes blue. At times if there was a silver fuselage and a cheatline then the windows were left clear and so appear silver (see the SABENA 737 below) but the cockpit was still black.
SILVER OR DARK GREY WINDOWS
In the 1990s most of the models were updated with silver windows but a few got dark grey windows instead.
Below: Dark grey windows are rare but appear in quite a few Lufthansa and Condor releases
Around 2003/04 the silver windows gained a shadow effect and many colours were updated with the new style windows. I have to say that I'm not a big fan of these windows and preferred the previous version. In the photos below where the Northwest 747 has silver windows the shadow outline is in white not black.