How to measure a canoe: length overall - the total length from the outermost curvature of the stems; beam - maximum width (which is usually amidships and probably several inches below the gunwales; depth - from inside of planking at keel line to top of gunwales.
With metallic battens, it is probably not a Dunphy. To back up a little, wide board canoes are usually fitted with battens to cover the seams between the planks to make the hull waterproof. The earliest style of battens are sections of rib stock cut to fit the spaces between the ribs. A later style has a full length batten sitting in rabbets cut in each of the planks, the batten is under the ribs, when seen from inside the canoe. Some builders, like Walter Dean, used metallic battens instead of wood to straddle the seam. From reading the catalogs, it appears the Dunphy style battens were pine, thicker then the ribs and notched to fit over the ribs.
Given that yours has metallic battens, I would suggest looking at Walter Dean and maybe some other Canadian builders to find a positive identification.
Pictures here would help...