Back when I painted my first Techmarine I did a quick image search for the Ad Mech cog and skull emblem to get the colouring right:
However, when I came to paint my
Galvanic Servohaulers I got to the large skull at the top of the crane and realised that I had everything backwards. It was obvious that the side of the skull on the viewer's left is bionic and should be coloured black whilst the unadulterated bone should be white. More like this:
Clearly this version isn't a simple mix up - the viewer's left side of the skull is black because it is cybernetic, which is a deliberate choice. This led me to believe that this colouration was correct.
However, after further confusion I have checked the Ad Mech codex itself and I now realise that both versions of the emblem appear. I would say that the majority have the black skull half on the viewer's left but there are also several examples with the white skull half on the viewer's left (e.g. Skitarri Legions guy on page 14).
Is there any lore reason why the emblem would switch back and forth in-universe? Do the two different versions have different meaning? I find it hard to believe that a cult of logic-obsessed robot men who dogmatically cling to ancient traditions would play fast and loose with their own iconography.
Even out of universe, whilst I realise that accidentally flipping the logo is a possibility, I would have thought that it wouldn't be that hard to keep consistent. They seem to be able to avoid mirroring things like the Imperial Fists emblem or the Slaanesh symbol.
Thoughts?