Diplomatic Courier Service Gold Medal

First day of issue envelope containing first day of issue gold medal:
Medal:
Face of coin reads "Diplomatic Courier Service" with an olive branch or flourish around the circumference. There is an eagle in flight occupying the center, both wings fully outstretched upwards, flanked by the years 1918 and 1968.
Reverse side of coin reads "United States of America" within the circumference. The center contains an inscription "None is swifter than these..." with a sheath of some sort above and crossed olive branches or fronds below. "P" is stamped just below and between the stems of these fronds.
Envelope:
First day of issue across a 15-cent US stamp: XX Olympic Summer Games Munich 1972. Nickel-sized postal stamp "Washington. DC Aug 17 1972." Upper left front envelope printed in brown ink: United States Diplomatic Courier Service /Commemorative Medal ~50th Anniversary / First Day of Issue / Gold Medal
Below the coin are 4 Greek words both preceded and followed by ellipses. A Greek name follows as if attributing the preceding quote.
Finally, the very bottom, left of envelope: Official first day cover sponsored by the U.S. Diplomatic Courier Association.
Reverse side of envelope a more elaborate "postal-style" stamp over the flap and envelope body: U.S. Diplomatic Courier Association (top circumference), Washington, D.C. (bottom); inner circumference (circle) containing "Commemorative / Medal / Aug 17 1972 / First Day / Of Issue."

Item is contained in a heavy, protective plastic sleeve.

I have found no information or literature as yet. I do find it interesting that the philatelic recognition trails the actual 50th anniversary by 4 years.