What this coin looks like (obverse, reverse, mint mark location, special features, etc.):
The 1981 S Proof Kennedy Half Dollar was produced in two types. One type was the Type 1 Filled S in which the mint mark was not as clear and partially filled in - depicted on the left side of the mint mark comparison image. The second type was the Type 2 Clear S in which the mintmark was clearer and larger - depicted on the right side of the mint mark comparison image.