Cab interior colors - Model Railroader Magazine
Here's an obsolete paint chart from NYC drawing No. X-73756 Lettering Numbering & Painting Diesel Locomotives dated December 11, 1946 and made obsolete on 10-24-1963. Obviously, CB&Q may have specified other colors but here is a reference to the Suede Gray for the engine room and Dulux Green for the cab interior.
I do recall spending time in many F-7s in the Cleveland area and the cab interiors were still the Dulux Green then (early '70s) When engines were shopped cab interior repainting was way down on the priority list so I would guess many went to the scrapper with the original Dulux Green.
Here's a photo in the cab of Wabash 671 in the Bellevue, OH NKP Museum. I would assume the museum folks kept the restoration as accurate as possible so here is an example of light gray. Perhaps there is a Burlington Route historical society that may be of help? In THIS PICTURE anyway, you can see the Barco speed recorder IS green!
Thanks, ED