I honestly have no idea. I originally thought that they were for the jetpack mode or something but you really only need two for it to clip into place. I'm not sure why there is four at all unless they're thinking down the line of another mold.
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The extra holes are for Sideswipe, so he can mount the backpack.
You have to give huge props to the Hastak designers for planning 2 distinctively different figures from the one mould from the very beginning! :)
That Sunstreaker/Sideswipe mould is just about perfect! (& we may even get a 3rd completely different figure from the same mould at Botcon... ;))
Extra holes might be just the thing for some flashing lights to be added... But maybe I'm just being paranoid... ;)
This is more like a first impression, as i've only just unboxed and had a quick play with my first Universe (Henkei in this case) toys today. Personally, i feel both Sunstreaker and Prowl's robot modes are far better than their BT/ALT incarnations, thus making them the definitive versions for me! I'm anxiously awaiting the next few deluxes now!
Maybe the roof holes are like Paulbot said, for flashing lights.
I would be happy if they do a Red Alert repaint!
I'm just siding with the realistic option!