U.S. Marshal Sam Buckhart arrives in North Fork to look for Indians who are suspected in the brutal murder of a Ranger and his family. (This is the pilot for the series "Law of the Plainsman." )
A renegade band of Indians captures Mark and disappears into the hills of New Mexico.
From "The Rifleman Episode Guide"
The case could be made for Deputy Marshal Sam Buckhart to be eligible for membership in the TV Crossover Hall Of Fame, but on the Birthday Honors List - if only we could find another TV role played by Michael Ansara who could be Buckhart under another name. (Even if his return to 'The Rifleman' happened after his own series had launched, it wouldn't have counted as a separate qualification; it was still 'The Rifleman'.)
It would take a lot of research (which I just don't have time for) - studying episode guides, actually watching the episodes, - to determine if all of the factors aligned. The character would be working undercover, so the difference in names wouldn't matter, but he'd have to be revealed as a good guy by the end of the episode. The timeline would have to match up to 'The Rifleman' and 'Law Of The Plainsman'; it could take place prior to those shows since he was already in full operation as a U.S. Deputy Marshal, but Ansara couldn't look older than he did in "The Indian".
There might be a few candidates, but right now I can think of only one character that might work. And it's a dark option.....
Michael Ansara was in an ABC TV movie of the week back in the 1970's called "Shootout In A One Dog Town". He played a lawman who staggered into a small town and charged the town banker to keep the $200,000.00 he was carrying safe, no matter what - before dying from a bullet in the back. His character was identified as "Reynolds", but he may have been carrying falsified papers as part of this undercover operation. So it's pozz'ble, just pozz'ble, that he was in actuality Marshal Sam Buckhart.
If so, it's a hell of a way to get into the TV Crossover Hall of Fame.....