AFAIK, the Comet Herald was only used on passenger car drumheads, though it also might have appeared on timetables.
I don't believe the SN ever used heralds?on their boxcars, just the arched "Sacramento Northern" lettering. The Northern Electric did use the Maltese Cross herald on their boxcars and some may have survived unchanged through the 1920s. Most surviving NE boxcars were scrapped shortly after the great merger.