The comment made by the two boys walking on the highway when Malloy asks them if they know what they're doing wrong refers to the rule taught to children during the era when this show took place to walk on the side of the road facing traffic when there are no sidewalks so as to be able to see approaching vehicles, which they would not be able to see if they were on the other side of the road (i.e. the vehicles approaching them would come from behind them).
The liquor store that appears in the beginning when Reed and Malloy are investigating the robbery was located right next door to the taco stand that Reed and Malloy dined at the previous week in Log 91: You're Not the First Guy's Had the Problem (1968).
The car over the embankment has no rear license plate. Those are usually protected by design when the car is built.