Dan:
Like JHZ posted above, I also have a set of those cars which I purchased directly through my membership in the K-Line Collector's Club back in the day. I don't recall having to install any window strips as that would have required taking apart the cars. However, that was long enough ago that I could be wrong on that point. But I do remember adding the included diaphragms to the ends of the cars.
BTW, you used the word "silhouettes" but only one car has silhouettes of people in the window strips and that is the RPO car which has silhouettes of the mail personnel working inside the car. The window strips in the other cars just have outlines of horizontal window shades on the windows. So the "silhouettes" you have may not be intended for those cars.
I run mine behind my MTH Railking Torpedo, which although Brunswick green, has the same striping as the Tuscan FOM cars and IMO they look great together.
Bill