Different versions of Atramentized Knipex pliers?

Are there different versions of the Atramentized pliers wrench using different materials or a different coating? They always have the same model number, 8601XXX, but I've seen some that are basically pitch black and others that like a dull gray. And no, I'm not talking about the chrome version, that has a different model number and is quite apparent.

It is also not lighting or photo coloring differences, I've seen them side by side before.

Here's an example: https://old.reddit.com/r/KnipexOfficial/comments/1lrbip9/my_collection/

Look at the two Cobras in the middle of the picture, one with teeth protectors and one without. Both have the same model number, 8701250, but one is significantly darker than the other.