For a brief time in 1943, yes 20 and 455 had the sunrise herald. However 20 would have had the "standard" sunrise before the wreck plus a different cab. Post wreck 20 had the non standard skinny sunrise.
So this charter is not perfect but it is a fantasy charter anyway.
To be correct 455 would need to be post wreck, or 463 with the flying grande or 20 with a different cab and 1 of 2 different lettering styles, and 0400 without the sunrise depending on the options above.
BTW I say sunrise herald while others use sunset, or sunburst. I learned early on to call it sunrise, any of the above works really. Who knows what the RGS actually called it.
Jeff Taylor
CRRM curator of equipment and rolling stock.