'Cause that's no Sunderer in my opinion, unless it's HEAVILY customized.
Teaser pic,
Sunderer pic #1,
Sunderer pic #2,
Sunderer pic #3.
The Sunderer's wheels are proportionally smaller, and they aren't spaced out so wide.
Its driver section contains a proper hood, not a single 60-degree surface.
Its rear section is vertical, not sloped.
Lastly, we haven't seen one with those three thingamajigs on top, nor with an antenna.
Of course the Sunderer has changed a bit over time (as can be seen on the 3 different pic shown so far), but I'm not convinced. There's also a chance that the Sunderer's pic wasn't cut out too well, but let's assume that that isn't the case.
So either that's somehow a Lightning (it would have to be tracked now, and have a forward-facing, narrow aiming arc gun, rather than a turret), or a Deliverer (or any other PS2 equivalent of BF3's Hummvee/Vodnik).