All were dated 1776-1976 and featured new reverse designs to celebrate the Bicentennial.
Dennis R. Williams designed the new dollar's reverse design. The Liberty Bell is superimposed on top of the moon. Dual-dated coins were struck at the Philadelphia and Denver Mints. Proof coins struck on both silver-copper and copper-nickel planchets were made at the San Francisco Mint.
These are not very rare, but they can be in high demand from registry set collectors. This 1976-S Eisenhower Silver-Copper Clad Dollar graded Proof 70 Deep cameo by Professional Coin Grading Service sold for $1,242 at GreatCollections on Aug. 1. Most examples that have crossed the grading desks of PCGS have been graded Proof 69 Deep Cameo -- 40.512 as of August 2, while 166 received a "perfect" Grade, which is a small percentage of the original 4 million.