its called a repaint XD
Thank you Joseph for the very helpful reply...

If you would have actually tried to make a repaint for the PMDG 737
without eyebrow windows before replying, you would have noticed that even if you put some paint over them they remain partially transparant as they are hardcoded in the aircraft model.
The original poster mentions his shots are unedited so I'm wondering how he managed to get rid of the cockpit windows 4 and 5 (hexediting of the mdl file maybe?)... unless he is using another model than the PMDG one.
Cheers,
S.