It's partly the "gestalt" - look at enough of these things and you get a feeling. But also, the decks, seats, thwarts and stem profile are consistent with an RBMCo canoe. The seats resting on risers were only done by a handful (notably Rushton, but Rushtons will have trapezoidal stern seats and the rail caps, if original, are wrong for Rushton). You may find a short heart-shaped deck tucked up under that long deck, another characteristic. The planking pattern, not evident in the photos, would be another clue. You can read more about identifying the Racine canoes in Wooden Canoe issue 116.