S1274 is undated, and S1281 is not mentioned in the vessel-detail section of Nantucket Signals. The additional painted source is dated 1840–1850.
Sophia operated from Nantucket under John Cook in 1846 and 1848, with J. Cook Jr. & Co. as agent, and was sold to California in 1849.
Keep the explicit scope label independent; no alias or company identity is inferred.