One "USOPS Fables" First Day of Issue envelope

Abstract

Doris Gold Cachets" here will become simply "Doris Gold" in the next FDC I have, namely from 1988 for the "E" stamp. Apparently, the "C" stamp was originally worth $.20. The picture here suggests that the "A" stamp was worth $.15 and the "B" worth $.18. Consumers may not be happy to read that "Raising postal rates is as easy as...ABC"! How many envelopes and stamps might there be in all?