This is the info I found:
The U.S. did not strike quarters with the 1975 date. Dual-dated quarters bearing the date 1776-1976 were issued during all of 1975 and 1976 to honor the Bicentennial.
The U.S. did not strike quarters with the 1975 date. Dual-dated quarters bearing the date 1776-1976 were issued during all of 1975 and 1976 to honor the Bicentennial.