When Lester is about to perform the act of necrophilia and he places the rifle against the Pontiac, he initially places it barrel down but after he finishes his deed and they show the outside of the car again, it is barrel up before it falls down to the ground.
When Lester carries the dead girl through the woods, her right arm twitches upward twice in anticipation of grabbing the actor when he attempts to lift her again.
Lester seems to have an endless supply of bullets.