Possible Clues:

• When fighting was over mail turned green
• After, say, 1945
• Period during which there is competition for mail services
• Mail system run by Washington state after nineteen forty five?
• Battles for jobs after 1945?
• Antebellum antonym
• Job was cut short - Rex in late forties or fifties?
• Occurring after 1945, e.g
• Since '46
• Conflict in the mail-room since the last delivery from Germany