I know there were some shots of Luthor with curly hair (probably a wig), but you guys are right, the first season has him with dark brown hair.
And I love comments - they point out what the next section needs to elaborate on. - Would Deter care about Lois if she wasn't Luthor's 'ex', why was Lois not picking up on Clark's worries about Luthor (and was the threat Clark remembers a real event?)