A very funny comic!
I sometimes wonder: how does a comic, drawn by a belgian/french painter, who had visited America, appear to the americans, who are used to the Westerns? Is it very different/strange, or almost authentic?
Authentic to the real wild west, or authentic to movie & TV westerns? 
I haven't read this series yet so I can't comment on if it seems authentic or not. (However with all the mythologizing that the wild west has gotten starting with dime novels in the late 1800s I wonder if any Western can be truly authentic.)
And speaking of European Westerns, I believe Jean Girard (Moebius) had an early success with his Blueberry series.
KAM,
authentic to the real wild west and authentic how americans see the wild west. After all, the image a person has is not only made by the bare facts, but often by the first movie/novel about that time one has read/seen.
The Blueberry series is not bad, but a different style (realistic, serious). Lucky Luke is not-realistic and intentionally funny.
Can you get European comics in your book store?
Probably. I have seen Lucky Luke collections offered for sale in catalogs & online as well.
BTW, the creator of Asterix, Morris, spent several years in the West, doing research, and its said that many of the people appearing in the Lucky Luke series are historical (sometimes, there's an extra page at the end showing a b/w photo of the historic person with a few lines of bio.)
Its also interesting that Lucky Luke is one of the comic heroes I know of that changed his habits clearly in response to comments: in the early comics, Lucky Luke smokes hand-rolled cigarettes, and we often see pictures of him hand-rolling a cigarette as a sign of how calm he is during a critical/dangerous situation. Several years ago, however, Morris was told of how much smoking heroes influenced children to start smoking themselves, and Lucky Luke stopped smoking. Even the head on the left-hand corner of each album now sports a long blade of grass Luke now has in his mouth (to chew on, presumably, or to look cool under fire).
Mark Trail (a nature newspaper strip) used to smoke a pipe, & sometimes used it as a pointer, and because of negative comments stopped smoking.