This was the last aired episode.of the series.
Christine Belford who portrayed Sheila Redman, the ghost from season 2; episode 6 The Beast in Black comes back in season 3; episode 9 Thirty Seconds Over Little Tokyo to play a different character Dottie Parker.
When Dottie is introduced to Bill, the picture of Bill is flipped showing his breast pocket and flag pin on the right side of his jacket then a few seconds later its back to normal.