Well, I wanted to make sure before I brought up the following point. And before I get labeled a conspiracy theory wack job, I haven't formed an opinion conclusively either way.
But, I've stood in that window on the sixth floor, which is now a museum. I estimate the height of that window to be between 65 and 75 feet off the ground.
At that height, the angle of a projectile shot out of that window at that limo relative to horizontal would be at least 45 degrees, probably closer to 65 degrees.
That rod showing the alleged projectile path through the wax head is almost at a rise from back to front, relative to the head. At that entry point from the rear, a projectile coming from that high of an angle should have exited down around his eyes
I'm no pathologist, but when I shoot deer out of tree stands at the same angle, the exit wound is never higher than the entry point.