If the carcano was not the murder weapon ( and it wasn't).....then who cares if it was ordered by Lee Oswald or Mickey mouse?
What a great psychological insight into the CTer mind. Here we learn that Walt is not interested in who actually ordered the MC rifle that the history books conclude was used to kill JFK. The objective is to exonerate Oswald. Not to figure out who was behind the grand conspiracy. Why? Because any analysis of the facts and evidence of this case can't be reconciled with any consistent conspiracy narrative. So the objective must, by necessity, be limited to pedantic, defense attorney-like nitpicking of the evidence against Oswald even if, by implication, what is being suggested as an alternative makes no sense.