Mint Mark: No Mint Mark. In 1971, the minting center in Philadelphia produced over 155 million Kennedy half-dollar coins. Like previous units, the 1971 half-dollar coins from Philadelphia have no mint mark. Although the mint didn't have the highest mint that year, nearly all pieces entered circulation.
That explains why it's difficult to find a 1971 half-dollar specimen in uncirculated condition. However, they are not super rare. According to NGC, a 1971 no mint mark half-dollar in circulated condition can sell for slightly more than. However, there are a few 1971 half dollars that have reached impressive prices.