1) The Linclon Kennedy was driving in was completely gutted and rebuilt within 48 hours of the assassination. ... Why ? It was crime scene. This has never been explained other than they did not want it to become a curio. That is all well and good but it should have been left in tact until after the investigation. It was not. Thus it is reasonable to state that the crime scene itself was never, ever studied. If Kennedy was hit in the throat from the front there would have been a bullit hole in the seat where he was sitting. Unfortunately we will never know.
2) All the lamposts and signs were changed in Dealy Plaza thus preventing it from becoming possible to recreate the events independent of The Warren Commison's version which was done very shortly after [The next day I believe. ] along with all signs [the one that blocks our view in the Zapruder film was also moved] all manholes were covered over and from what I understand the original plans destroyed.
3) If one views the films and looks at the pictures it is obvious that other people were both filming the motorcade and taking pictures. Not all of these have surfaced. Where are they ? See this image below.