'The Fall Guy'
From Wikipedia:Played by Doug McClure, the character of Trampas took on a completely different personality from the character in the novel. In Owen Wister's book, Trampas was a villain throughout the story and at the end was shot by the Virginian. However, in the TV series, the producers chose to make Trampas a fun-loving and rowdy character, Doug McClure fitting the part perfectly. Trampas, a sandy-haired, rowdy cowhand who eventually settled down on the ranch, was by far the most developed character in the series. Several episodes were made detailing his past. Doug McClure, as Trampas, added a touch of light comedy to the series to counterbalance the Virginian's serious manner.
With his appearance in the movie "Maverick", I see no reason why McClure couldn't have been playing Trampas again. Basing the date of the movie around 1910-13 (due to Garner's age at the time and its correspondence to the birth of Bret Maverick), Trampas does show he's a "bit" older than he looked at the end of 'The Virginian'. But life as a ranch hand for so many years might have caught up with Trampas fast in those early years of the 20th Century.
Or... it could be that it might have been make-up to disguise him from being recognized as just a ranch hand. It could be that Trampas was serving as a front man for whoever owned the Shiloh at the time, that they were depending on his skill with the cards.
But again, I don't think aging had much of an effect on the boyish Trampas.
The same couldn't be said for the Virginian however.....