The tragic death of Pete Duel on December 31, 1971, was not acknowledged by ABC when the next episode aired as scheduled on Thursday, January 6, 1972.
In the UK, fans of the show were so upset by the death of Pete Duel, that the BBC decided to rest the series in early 1972 before the introduction of Roger Davis. The Roger Davis episodes were not seen until over a year later after a repeat run of the Duel episodes.
When it was broadcast in the UK after its run on U.S. television, it became one of the most popular American shows ever shown in the UK. So popular was it, that a later British show used a title that was a parody of it, Alas Smith & Jones (1984) (originally Alas, Smith & Jones).
Roger Davis played a Smiling Gunman in season two, and was killed by Kid Curry. Davis returned to the series to replace Pete Duel after Duel committed suicide.
The exploding saloon in the pilot opening sequence is Madam Orr's, from "Support Your Local Sheriff."