All I have is photos. The one here shows a good amount of construction details. The owner thinks 1940s from his memory. He can't find any numbers, plaques or decals.
I read through the 1922 Mullins catalog , and page 5 does say they only make open gunwales canoes. So now I'm not sure. I'll try and look a little more.
Yes I agree, the owner will be bringing it to me , but not till Sep. or Oct. So I'll be able to inspect it closer. I have a couple more photos so maybe the closed gunwale is original.