And that a rifle with serial number C2766 was found at the scene of the crime, with Oswald's fingerprints on it.
I don't understand where you are going with this. Oswald ordered a 36" rifle, was sent a 40" rifle. He apparently didn't complain, and he didn't return it.(you need to show proof that a 40" rifle was sent by Klein's as a substitute for the 36" rifle) Somehow, that 40" rifle shipped to his POBox (provide documentation that a 40" rifle was shipped to PO Box 2915)ended up in the 6th floor of the SBD. Oswald's rifle in the Paine garage was missing, and he was seen bringing a package to work (he claimed them to be curtain rods, but no one saw inside it).(LHO never claimed that they were curtain rods, curtain rods is what Buell Frazier said)
What difference does it make that he ordered a 36" rifle? That's not what they sent him, for reasons discussed (they had switched by the time they got his order and so sent him the currently advertised version)(you are incorrect, the ad ran in April and the product was shipped in March does not matter as the product shipped shows it being a 36" rifle). It was still his rifle, and he still used it to shoot the President(you have to show it was his rifle).