We already got more informations about it even.
It's not really anti-grav. It uses a fake anti-grav technology that "pushes" against the ground. An Iron Warrior that wanted to place a melta bomb beneath it got flattened by it in the Dark Imperium novel.
I don't think it looks too similar to our stuff. It looks like a combination of a Land Speeder and a Predator but made more bulky. Fits the more burtal looking Space Marine designs and the lower technological level of the IoM.
So yes you are being paranoid here.