Correct. A point for you. The vehicle was commissioned to Aria Group in 2012 by 343 Industries, a subsidiary of Microsoft responsible for making "Halo 4", to use as a promotion tool at Comic-con and E3.
From the L.A. Times:
"Mark Ferrara, chief project manager at Aria, says this kind of experience made the Warthog project relatively easy.
"We build so many prototype vehicles," Ferrara said. "This was not a particularly challenging vehicle for us."
Ferrara's team spent six months creating a Warthog body identical to the video version, down to the smallest detail: fake rivets on the industrial-grade foam or plastic reinforced fiberglass body panels, hand-holds to get into the vehicle, and the gauges in the Warthog's interior with static readouts. Even the horn has been lifted from the game and attached to a speaker.
The vehicle is essentially a pickup, with two conventional seats in the cabin and a truck bed. There are no doors, just a low sill. Mounted in the bed is a fake 50-caliber machine gun.
Underneath the hand-assembled skin is the chassis, transmission and engine from a 1996 Hummer H1. It has a 6.5-liter diesel V-8 engine and a four-speed automatic transmission. For safety purposes, the Warthog has a top speed of only 25 mph. But it can do more."