That been addressed. The optical sight was removed to allow it to fit in the evidence box. It’s immaterial.
It appears in the first photo that it might have had a optic viewer above the rifle. One that is easily removed from the rail.
If the optic was not Kyle’s, it would be logical to remove it.
The optic had nothing to do with the functioning of the rifle.
That would explain the absence of a front sight on the barrel.
I bought a .308 Savage rifle recently. It came with a scope mounted on it. It had no front sight or mount for one on the barrel. It is a very simple, clean design and is exceedingly accurate.