Conrad Bain is the only actor to appear in every episode.
This was not written to be a series finale.
Conrad Bain is the only cast member to appear in every episode of the series.
With their appearances in this episode, Gary Coleman and Conrad Bain are the only 2 cast members to appear in both the Pilot and the Series Finale.
ABC cancelled Diff'rent Strokes after only 19 episodes aired on the network. The show was brought back to Saturday nights in re-runs for the summer.
The characters of Mr. Drummond, Arnold and Sam are the only characters from the cast featured in this episode, the smallest amount of a cast to appear in a single episode of the series.