The earliest of the $50 pieces were produced under Augustus Humbert's name at a non-federal .887 fine standard. Soon after, Humbert's name was removed and the slugs were now struck under the name of the United States Assay Office of Gold but still at the same .887 standard. Things proceeded well for the Assay Office and even smaller denomination coins were struck. An unexpected blow came in the form of legislation passed in August of 1852 that suddenly forbade the Customs Office from accepting any gold coin not struck at the federally-mandated .900 purity. The Kagin-14 $50 pieces were the outcome of that crisis. Petitioned by the local merchants to alleviate the situation, Curtis, Perry and Ward began to produce prodigious quantities of the $50 slugs at the federal standard in January and February 1853, some 23,800 pieces in total, all bearing an 1852 date. Their popularity undiminished, the pieces continued to be used in commerce until finally the state's petitions for a branch mint were heard and the San Francisco Mint began operations. Once the mint was up and running, thousands of the venerable Assay Office $50 pieces ended up in their melting pots to be made into officially sanctioned coins.

Today, perhaps a few hundred slugs are extant in all grades and types, most of which are in circulated grade levels. Because of their huge size and weight (just shy of 2 1/2 ounces of gold), the coins were prone to numerous abrasions and edge dings and other impairments. Uncirculated examples are exceedingly rare and are enthusiastically sought after as the finest examples of a classic design.