In my search for back issues of the SEDXC bulletin to add to the web page, I got a box full of stuff from Dave K4JRB.  On top were two envelopes addressed to the SEDXC from 1978.  Inside were five "first day covers" for the Clipperton FC0X DXpedition from 1978. 

As the letter from Charles WA9INK says, they are technically not first-day covers since the stamps were already in use at the time, but may be of interest as souvenires to some of you out there who care about stamps.

Glad to hand/mail them to the first five who ask.

Here’s what they look like: