Up until the 1980s, Lex Luthor was more of a evil mad scientist in the Superman comics. It was John Byrne’s Man of Steel in 1986 that turned Luthor into the businessman most people recognize him as these days…and in that limited series Luthor wasn’t bald. And much like with the Man of Steel movie sequel, he doesn’t show up in that series until about a year after Superman’s first appearance.
The rumored background for Luthor in Batman V Superman is that he’s something of a street thug who made out well, and that too matches the characterization Bryne used in the original Man of Steel limited series. Luthor grew up in Suicide Slum, goes to MIT, and then forms Lexcorp. As we know David Goyer doesn’t really read comic books, it’s very possible his “inspiration” for the characters comes from such a well-known comic series.
Based on all of the rumors that are out there about what Lex will be like in the movie, it wouldn’t be shocking if they go for more of a look that’s something in-between the Secret Origins and Byrne Man of Steel looks for the character. That means it’s possible Luthor won’t be bald, and we’ll have to strap ourselves in for more internet rage from people who are unfamiliar with the comics.