I am trying to sort through a ton of first day stuff (letters and post cards) and came across something weird.
I have the top one as a "hinged pair" (with one unused, supposedly for reply) of Fist Day Issue of the 4-cent "New Postal Rate" dated 7/31/58.
I also have the bottom one as a single, used First Day Issue of the 4-cent "New Postal Rate" dated 8/1/58.
Why two different dates for the same FDI embossed post card? I'm supposing that this was not unusual although I have numerous other First Day of Issue pairs and they all match up.
I admit my lack of knowledge as I am trying to get through a large "attic find" that was inherited
Thanks in advance!