Probably a little true. My friend's late dog Chewie was a pug mutt, and so bumbling that he seemed incapable of sin. Sinning requires awareness of a larger shared world, and he was barely aware that he was in a world, or indeed even that he was at all.
He was content, just . . . not very present. Used to have staring contests with poles, stuff like that. Only thing that aroused his doggy brain beyond "lizard in the sun" were tomatoes on the vine, which he loved to murder.