Supply Sergeants Never Die - S2-E6
Continuity mistake: The Supply Sergeant Singer's second shirt button is buttoned as he approaches the counter, but as he continues around the counter it's not, then it's buttoned up again. (00:25:00)
Continuity mistake: While Gomer shows a little girl how to play jacks with sugar cubes, the number of sugar cubes go from 4 to 6 while the girl plays. (00:10:00)
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.
Bishop73