A backmark on a cuff-size button saying Fine Gilt L-something could be L&T, which is Lewis & Tomes, a button maker in Birmingham England, sho is known to have manufactured some US Nay buttons sometime between 1816 and 1833. Their New York City branch was in business from 1819 to 1826. The McGuinn & Bazelon book on button backmarks lists a US Navy button with a backmark saying "L&T / Fine Gilt / No." backmark. The US Navy button made by Lewis & Tomes is Albert's button NA44 -- but that's a 23mm ("coat size button) and yours is a cuff, so the emblem on yours is slightly different from NA44 shown in the Albert book.