Brothers Stunning and Brave (Emperors/Sons) looking for female Custodes in 20 years old Lore Book

Games Workshop said, that there were always female Custodes. So I asked Custodes Stunning and Brave (pronouns Emperors/Sons) to help me to find them in Visions of Heresy - The first big Horus Heresy Art/Lore book ever published. If they were always there and its not just some lazy retcon from GW, they must be there, dont they? After all, multibilion Corporations never lie to their customers. Or do they? 

Also, its quite interesting to see how was representation 20 years ago. You will probably by suprised. I was.