Ron Guth: Production of Half Dimes at the New Orleans Mint dropped more than 40% in 1854 to a still-respectable 1,560,000 coins. Not surprisingly, the number of certified 1854-O Half Dimes is 43% less than the number of certified 1853-O Half Dimes. Most of the 1854-O Half Dimes went into circulation, but there are at least a couple hundred Mint State survivors that collectors saved for posterity.
As usual, quality control at the New Orleans Mint was sub-par, and many of the 1854-O Half Dimes sport a weak strike, especially at the denticles. It is highly unlikely that a fully struck 1854-O Half Dime exists at all. The best example is a single PCGS MS67.
Heritage 11/2004:6146, $32,200 - Eugene H. Gardner Collection - Heritage 5/2015:98174, $18,800