I'm not sure if someone has already spotted this but the Mosquito in the teaser trailer had a chaingun under the cockpit where the teaser picture just has a hole.
I guess this means the teaser pictures don't have any weapons in them. There are two similar looking holes on either side of the reaver cockpit as well as that smaller one underneath it.
Perhaps this is something to do with the customisable vehicles, potentially the weapons aren't part of the model because they are customisable? I wonder if the pilot controls one of the guns, and if the gunner controls the other and the rockets. Or I could be completely wrong and they are just aesthetic air intakes on the sides