Norman Fortier most always noted the negative number on the verso of his photos. With that information you could contact the New Bedford Whaling Museum and they would be able to check the Fortier register.
You may also want to compare "your" schooner against images of the Keewatin, designed by Alden (with input from Carl Alberg and Fenwick Williams) in 1947 and built by Newfoundland Shipyards for Donald G. Parrot. See Carrick, John G. Alden and his Designs, p. 408, for photo and plans. Keewatin was often in Buzzards Bay during the time in question. Thus it _might_ be her. But some details don't match. Different chainplate details, apparently missing stern davits...