Some people here seem to be claiming it wasnt the same plane that went missing but cant prove it wasnt 100%.
This is mistaken. I've pointed out why, just above.
Did you know that besides the electronics, there are hundreds, even thousands of other components, each with their own serial numbers, that when installed are "paired" (in hundreds of pages of documentation) with the main ship's S/N?
Any mis-matches would be discovered, again by maintenance personnel. It is far more complex than some people seem to realize.