Many of you are "Too Young" to remember the reason that the "ribs - flutes - separation lines" were put there in the first place. You will also recall that the F-3 also had the ribs put in for a similar reason. A big fururor came about this when Lionel began the PWC Series and did the W.P. F-3's with the ribs (etc.) so that they had to redo the W.P. shells and exchange them for those who wanted a more correct version.
The reason: was to better separate the colors for the Santa Fe warbonnet paint scheme that MPC brought back. If you recheck the F-3 series, there are no ribs before that road name/scheme was done. After the S.F. Warbonnet, all the f-3's had the ribs, and the early alcos that MPC also did.
One can look at the QuickSilver paint scheme on the low end alco and see the ribs. As these were not highly collectable, no one cared too much about it on the low end alco; But a Post War Celebration Series - that's "a horse of a different color". The ribs do make printing letters and logos more difficult, but smaller, more elongated lettering can give a forced perspective of length to the units too, due to their shorter /smaller size.
Hope this helps you understand the why of the ribs, and what might be involved in changing it back. Dennis M.