Producer Herman Cohen: “Lawrence Tierney, Wayne Morris (he’d just left Warner Brothers), Dorothy Malone, John Ireland … for a cheap picture, it had a hell of a cast. And we signed a young guy who had never directed before, named Rod Amateau… For The Bushwhackers, we rented the Western Street from Warners, and we also used the Western Street at Columbia a couple days. We shot in and around town, we didn’t go on location any further than the Western Streets.”
From a Tom Weaver interview found at The Astounding B Monster — he forgot to mention Lon Chaney!

Does anyone know where I can purchase this poster
Sorry, I don’t. Can’t remember where I found that scan.
Good luck.