I really don't want to flame a US versus UK war, but I think there more evidence suggest what he is referring is something manufactured across the pond.

The question is what happening in 1823. It may not be a patent, but a Royal charter. The 1820's was a period when Chubb first expanded into detentions locks as Chubb archive article I linked to previously stated. Initially with padlocks, which as the article stated, became very popular in other countries, the US included? Don't know- probably. They also patented a dedicated prison lock in 1824, which is one I pictured. But as BBE pointed out during this period in the US, dedicated locks were rarely used.

But what is significant about 1823 is its the year Chubb became the official lock of the Royal family. Chubb locks carried this seal well after 1823, and certainly would have increased there esteem in the US. And a Chubb brother was making locks in the US at the time.

Also the lock the posted put up is Mickey Mouse shaped lock. The reason why 90 percent of the forgeries on EBay have a Mickey Mouse shape is that was shape of early Chubb padlocks.

So I think 1823 refers to the Chubb Royal seal.