I'm a bit confused. My understanding is that there has only ever been one version of the Apple Pencil, and the rumored Apple Pencil 2 won't be out until next year or later. However, I keep seeing Apple Pencils being sold all around the web and notice two different model/variants being listed. I know the actual model is A1603. But what does MK0C2AM/A or MK0C2ZM/A signify? I've seen both of these listed and have not found any explanation as to the difference. Any insight would be appreciated.