I respectfully disagree that Kubert was involved in this or O.S. 640 (another "Western Marshal"). Is there an interview somewhere that says he worked with Everett Kinstler? I have great admiration for Kinstler but I also acknowledge that he swiped like crazy in his comic book work. Check out the Kubert stories in Avon's "Jesse James," for example. You'll see that Kinstler not only was influenced artistically by Kubert, he also lifted tons of Kubert figures, even whole panels, for his own westerns. Looking at the totality of his Dell work, I'd say these "Western Marshal" comics were both pencilled and inked by Kinstler.
Link to the book:
0534 - Ernest Haycox's Western Marshal