A Little Chicken Soup Wouldn't Hurt - S5-E10
Continuity mistake: While Molly empties all the homemade food from her black bag onto Carter's desk and then the men eat, Molly's purse is either hanging from her left arm or it's gone, depending on the camera angles.
Answer: There's no indication they were meeting for the first time, in fact they seem to know each other as Sgt. Carter addresses Andy only as "Sheriff". Gomer Pyle just says his two favorite people are "meeting face to face", and obviously in the pilot episode Sgt. Carter wasn't one of Pyle's favorite people yet.
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