When it was later broadcast in the UK after its run on US TV, 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, 1984's Smith & Jones (1984) (originally Alas Smith & Jones).
This series often mixed fictional characters with real-life ones - even the two leads are that mixture. Jed "Kid" Curry was real, a fairly well-known outlaw who committed suicide when trapped (several episodes feature discussions between Curry and Hannibal Heyes on whether they will both stay straight, with Curry sure about Heyes and far from sure about himself).
Following co-star Pete Duel's sudden death on December 31, 1971, production on the series came to a halt for only half a day. Filming resumed on the afternoon of January 1, 1972 with Roger Davis re-filming Duel's scenes for the episode in production at the time of his death.
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 to be seen until over a year later after a repeat run of the Duel episodes.
George Peppard was also in the running to replace actor Pete Duel before Roger Davis was chosen. Davis was already acting as the narrator of the opening credits. When he was added to the cast, a different narrator, Ralph Storey, was brought in to do the opening credits.
After Pete Duel's suicide, it was decided that the episode then being filmed would not be shelved until a replacement for Duel could be cast and re-takes filmed. Voice actor Paul Frees was brought in to dub in Duel's voice for some completed outdoor footage whose audio tracks were felt to be of unsatisfactory quality.
Kid Curry's wanted poster reads as follows: "Kid Curry. Reward $10,000. Offered by Midwest Railroad for the capture dead or alive of Kid Curry. Age, 27, height, 5 feet 11 inches. Weight, 165 lbs. Dark blonde hair, blue eyes and even features. Medium build. He is the leader of one of the worst bands of desperadoes the Territory has ever had to deal with. The above reward will be paid for his capture or positive proof of his death. Dead or Alive! Kid Curry." Hannibal Heyes' wanted posted is identical except for the different name and that his personal description reads: "Age, 29, height, 5 feet 11 inches. Weight, 168 lbs. Dark brown hair, brown eyes and even features. Medium build."