Do radar guns have a sightine or something to aim with

Hello,
I in the midst of preparing to dispute a speeding ticket. I wasn't speeding but was getting passed by someone who was speeding my argument (should the cop show up) is how does he know he was aiming it at me. Does he have a sightline on his gun?

Radar units put out a cone-shaped beam. Most will return the speed of the largest return signal. Usually, this is the closest vehicle, but it can be the largest vehicle. For example, given two passenger cars, it will lock on to the closer one. Given a fiberglass-bodied Corvette and a tractor trailer with a box trailer, it will probably lock on to the truck, until the Corvette is real close.

I've heard some newer radars display the speed of the fastest target in it's view area.

Either way, it is up to the officer to determine which vehicle is the one responsible for the indicated speed.

Lidars (lasers) have a sight. That is a big advantage - as long as the laser unit is stationary, and the sight is properly adjusted, the speed indicated is the true speed of the vehicle the officer is interested in.