I have a 1673 farthing O sideways/O and as with most of these errors they only list as EX-Rare.What value are we talking figuratively .I also have a 1843 half-farthing unc .I can only describe ddr as a 3 legged trumpet double dated 8/8 . multiple 4's over small 4 . 3 doubled.Must be the strangest to exist .Any Idea of value.
For something like that determining value is a two-step process. First, have it authenticated by a top level authority - a major third party grader, a major auction house, etc. Second, sell it at a well advertised major auction (NOT an online auction). What it brings will be what it is worth.