I thought the OP was quite clear. I understood that they were asking whether the AT300s for TPE, in common with the new Crossrail stock, would have black ends.
The answer is, I think, that no one knows for sure yet. It's now possible to have trains with a different colour end to yellow, assuming it meets other characteristics (the correct lights, I think). I imagine the mock ups with black ends implies that this is the preference, however there might be reluctance in TPE to be the first TOC to make this change, especially if there is likely to be any objection (from, for example, staff or unions should they believe the change to impact safety).