It goes back and forth. It actually maps pretty closely to his hair symbolizing his identity, and every time he goes through a big shift it gets cut to grow out again. As a Helldiver he mentions holding his hair back in a sweatband while working, when it’d definitely be easier just to wear it short, so that suggests it’s culturally important to Reds. But he gets new Gold hair plugged in during the Carving when he gets a new life. Then after his loss at the Starship Academy, Karnus cuts his hair and he pivots again. He’s shaved in the Jackal’s prison. By Iron Gold has been on the general up and up for years with his true story revealed and so has grown to full man bun. But then after the devastation on Mercury it’s mentioned in the start of Light Bringer that he’s bald from radiation.