Arnold's wears a future suit

Gary Coleman played Hieronymus Fox in two episodes of Buck Rogers in the 25th Century
"Cosmic Wiz Kid" November 15, 1979, and "A Blast for Buck", January 17, 1980.

And I was surprised to see Arnold wearing Hieronymus Fox's futuristic space suit like costume in an episode of Diff'rent Strokes.

It seemed a lot like breaking the fourth wall to me. And then I thought that maybe Diff'rent Strokes happens in an alternate universe where different science fiction shows and movies were made, including one with a character wearing a costume that looks like the one Buck Rogers in the 25th Century. And maybe copies of that costume were sold to kids because that character in the hypothetical movie or tv show was very popular.

Anyway, I wonder which episode(s) Arnold wore that costume in.