.. because the colour reproduction process, from the photography, to the display on somebody's computer monitor introduces too many factors for errors.
First of all, the "dial" on the Freak is in fact a semi-transparent sapphire disk, which again is the mainspring barrel's upper lid. And it is dark blue - on all Freaks I am aware of. If a picutre is not taken in strong and direct lighting, though, this semi-transparent dark blue might appear as non-opaque black.
Best regards,
Marcus