First of all,
Chicago Great Western. Apparently in 1949, the president wanted to de-emphasize the 'Chicago' part, but that doesn't make it right.
The CGW bought two former MILW cars in 1961 for trains 13/14 between Minneapolis and Omaha.
Matt would have to add the ribbing like Bill did and there is also a small extension at the bottom of the sides that's sort of a modeler's choice it's so slight.
But perhaps the biggest tooling cost would be making the car with the vestibule doors open.
Jason