This seems a good visual match for the leg seen in the underwater photograph from last year's dive.
Some commenters have observed that, had the damage to the stern of the "Erebus" taken place prior to or at the moment of its sinking, smaller bits of wood such as the table-leg would have had enough bouyancy that they might well have floated to the surface; that they did not suggests that the damage occurred long after the sinking, perhaps when the ship's superstructure was scoured by a passing iceberg. The Inuit certainly recalled that, after the sinking of the ship at Utjulik, they were able to recover casks, boards, and other pieces of metal and wood; these may well have been from material that had been stowed on the deck, while items below deck, such as the table, remained there and became more thoroughly waterlogged.
But we actually do have another leg to stand on: in 1949, Henry Larsen -- who had himself navigated the Northwest Passage twice as the captain of the RCMP vessel St Roch -- came to King William Island and searched its western coasts. There, among other objects, such as iron knees that doubtless came from a ship's boat, there was a turned wooden piece that appears very much like the leg of a similar, low table, about two feet four inches in length. It was apparently recovered from some point on the coast between Victory Point and Cape Felix; if indeed it came from a similar table abord HMS "Terror," then that vessel must have suffered a fairly catastrophic fate -- it would have to have been crushed in the ice severely enough that furniture from the great cabin would have broken free of the wreck and drifted to shore. And so, while I hold out some hope that the site of Terror's sinking may be found, this sort of evidence tends to give credence to fears that the wreck may be fragmentary -- what parts of it could be recovered, the Inuit surely took and make use of, leaving perhaps only a partial hull, or even just a field of débris.
[Image of table leg courtesy of Doreen Larsen Riedel; with thanks to Ship Modeler for his thoughts on this artifact.]