I was surprised, though, as I read through The Painter that Luke was not brandishing his trademark cigarette. Rather, he had a piece of straw/hay in his mouth. I thought perhaps that the art had been altered for the U.S. printing, much like how Sanji's cigarette was changed to a lollipop in some editions of One Piece when it was imported from Japan. But then I came across a scene in which Luke turns down smoking a peace pipe with an unnamed Native American chief because he "quit smoking a long time ago."
(I'm going to deliberately gloss over the inherent racism and stereotypes in these stories for now. It's not an insignificant issue, to be sure, but I haven't researched that angle very well yet to speak on it. So that'll have to be another post for another time!)
Now, it's certainly possible that whole panels were redrawn here and the script was altered in the translation to accommodate that, but that seemed unlikely. Doing some digging, though, apparently Luke's famous cigarette was discarded in 1983 and this was indeed done to better accommodate American markets. The Painter story I came across was first published in 2001, so Luke had indeed quit smoking nearly two decades earlier.
Interestingly, though, in going through the cross-sell pages in the back of these books, they sport the covers of the other 50-some Lucky Luke books that current American-rights-holder Cinebook has out. And in none of them is Luke smoking. He's either shown without anything in his mouth at all, or with that same piece of straw/hay. But, in comparing those covers to the original French versions, though -- many of which use the same art -- we can see that Luke was in fact smoking originally and that, for the covers at least, Cinebook opted to edit out the cigarettes.