Nantucket Signals assigns J152 to 1832 and J153 thereafter despite ownership changes. Its note “no border on flag haul and fly” appears inconsistent with the illustration and painted source. The painted M has a shallower V.
Japan is dated 1823–1849 by Loughran, but Nantucket Signals begins in 1822 and gives no disposal. Owners included Paul Mitchell, Alexander C. Mitchell, Levi Starbuck and Edward H. Barker. Agents included Paul Mitchell & Sons, James Athearn, and Barker & Athearn.
Keep the explicit scope label independent; no alias or company identity is inferred.