Revzilla started in Philly (downtown on Delaware Avenue) and a few years ago moved to a large facility in the former Philly Navy Yard.
They also have a Las Vegas warehouse that performs a bit of fulfillment.
It wouldn't surprise me if some of their manufacturers drop ship products direct to customers. Though I can't confirm whether or not they do that, if that is the case, then a shipment could in theory come from anywhere.
Plus they have some sort of growing strategic alignment with Cycle Gear, so that could change fulfillment points as well.