No, he definitely was not. Like other early Golden Age super-powered (and non-powered) heroes Superman, though always on the side of law, order and social justice, was capable of brutality (and a certain grim pleasure in it) that would be unthinkable for the character just years later. He was willing to kill; in one of the earliest Superman stories, he sent several gangsters out the window to their death. Just as Batman in some of his earliest tales used guns, and expressed satisfaction over the demise of crooks even when he didn't directly kill them ("A fitting end for his kind" and "Death...to Doctor Death" were typical end-of-story lines for him).