CNW GP38-2s 4600-4634 (35 units) were ordered by the Rock Island and financing had been arranged, but RI did not take delivery because by that time the RI's management was no longer in control of the property, the KCT was running the RI under directed service and the handwriting was on the wall.
The ex-RI units were easy to spot on the C&NW at the time since they were built to RI specs (five-chime horns and no "gong" bell on the nose) and they were the ONLY GP38-2s on the C&NW roster. In fact, they were the only GP38-2s the C&NW bought new (the others were secondhand purchased in the 1990s).
None of these units ever made it into RI paint before the order was diverted to C&NW. I know several people that work/worked in the offices at EMD that scoured their files looking for evidence of any being painted or of a proposed new RI paint scheme, but no such evidence was ever found.
The "hot" rumor at the time was the light blue would be replaced by black (leaving the white portions as-is), changing the big "R" to light blue and the road name "THE ROCK" to "ROUTE ROCK", similar to how some gondolas and coil cars were painted in 1979. Have never seen any evidence of a locomotive ever painted in these colors.
The very last locomotive to be painted by the Rock Island was rebuilt GP40 3004 in February 1980 and it was baby blue and white like the other GP38-2s.
There was some other related info on propsed RI locomotive orders and roster reorganization/renumbering that I posted on another thread a while back if you're interested.
Hope this was helpful,