Hard to say. On the one hand, like you point out, the hinges are atop the cane.
On the other hand, the seat bottom is the classic Rushton trapezoid (not possible to determine if it is assembled with mortise and tenon), the overall seat base is the same shape as the other styles, the back support and three-holed base are typical Rushton, as are the hinge style. The whole base is well-fitted, (or was, prior to shrinkage over time), and the seat bottom is mounted to the rails with dowels through the sides, which were subsequently pinned with brads.
It's made of cherry, and has that classic vintage cherry look.
I have found no images showing a seat of this style, and none of my pre-1893 describe anything similar.
It did come out of Canton.
I'm inclined to believe it is Rushton until proven otherwise, and may be an evolutionary stage, or a "quick, fill an order with what's on hand" type object.
Also, apparently one of the Adirondack antiques appraisers who is knowledgeable about canoes also told the auction house that it was Rushton. FWIW.