Love that engine, Sweetest little thing between the rails in all of steam land.
Just after the turn of the century (1900) all roof walks (wood or metal) had to be converted to 24" wide. Metal ones had to be of approved traction type, and the tops of wooden ones were NOT to be painted. In latter years, when wooden cars were gone, and brake wheels were moved to the ends and off the roofs, and only metal cars ran about (D&RGW NG or the likes being the only exceptions) cars often got “All Over Paint” Including those that still had roof walks. At some point, all roof walks were forced to be removed from cars, except for the likes of Covered hoppers where there was a need for access to the roof.
The sides and the bottoms of the roof walk boards, and the braces to hold the boards could be painted, Only the top had to be naked. Most all RRs took the cheep way out and didn’t paint anything that they didn’t half to.