An 18th century Silver Rattail form Tablespoon with single makers' mark, possibly American, circa 1730

I have been unable to identify the makers' name or origin of this spoon. The single stamp, which is the makers' mark, could be either American or British. The owner's initials in script appear to be American. If identified as American and by a well known Colonial silversmith, this spoon could be worth much more than I am asking for it.