It does look like the jacket is sleeveless and it's the long sleeve shirt that we see on the arms. The fabric is a darker maroon on the arms and the pattern through the material is wider than on the jacket. Should make it much easier to pose the arms as the thickness of the shirt will be much less than it would be with a jacket.
I think the arm armour have been attached to the arms underneath to prevent them from moving when you pose the arms. The same technique was used with the DOFP Wolverine. It hasn't been designed to be worn with a vest.
Perhaps there will be a Toy Fair exclusive version, or maybe they just decided they wanted to make a different looking Hawkeye this time. This figure is different enough that even if you got the first, you still might get this. I think the first one will still be sought after for people wanting to have both of the looks.
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