I know, Garfield! There's always something new to find out - the photos I saw over the weekend make it clear. Now, it's quite possible that lining was added before they entered traffic, as the pics show them "just out of the box".
The silver and green liveries followed each other, i.e. silver first, then repainted into green, and steam engines were mostly the same colour 1915-63, so the actual existence of variety isn't the same thing. the 121s were only grey until first repaint (into B'n'T), so it puzzles me as to why there seem to not two, or three - but counting red buffer beams - FOUR detail variations of the one short-lived delivery scheme.