This flag comes from the 1840–1850 signal painting.
Rosanoski questions Nantucket Signals: it illustrates M631 but the vessel account instead lists M630 for 1833, 1837 and 1841, annotated “flag is rotated 180 degrees”. That note appears to him to concern Maro’s M628 instead.
Martha is dated 1810–1849 by Loughran; Nantucket Signals begins in 1815 and gives no disposal. Recorded owners include Daniel Mitchell, ? Mitchell, ? Gardner, Robert Coggshall, Charles Bunker, James B. Russell and Charles W. Rand. Agents included Samuel B. Folger, James N. Bassett, William R. Easton and Peter Folger.
Keep the explicit scope label independent; no alias or company identity is inferred.