Here is part of what WIKI says about it. The Honorable Service Lapel Button sometimes called the Honorable Service Lapel Pin was awarded to United States military service members who were discharged under honorable conditions during World War II.[1] The award is sometimes colloquially called the Ruptured duck.[2] Sculptor Anthony de Francisci designed the award.
The Department of Defense awarded the button between September 1939 and December 1946 and it was made of gilt brass, except during metal shortages during which it was made of gilt plastic. Service members who received the plastic version were later allowed to trade it in for the brass version.