This work was done by local silversmiths. By 1850, most coin silver objects were made in factories from silver ingots, not coins. Coin silver disappeared. Coin silver from Philadelphia, New York, and Boston is common but still valuable. However, the most valuable coin silver is that from small cities and towns.
Local collectors pay a premium for such silver.
There are many books that help to identify the marks of silversmiths. Old Silve r. The Delaware collector needs Ruthanna Hindes' Delaware Silversmiths 1700-1850, which is now out of print. You read stories in the newspaper of low-number old Delaware license plates selling for thousands of dollars. Such plates are almost worthless unless the seller has the rights to the number and can transfer those rights to the buyer at the Department of Motor Vehicles. As an artifact alone to is worth a few dozen dollars.