They're going for a 'first Batmobile' look, like the old one from the 50's that was just a normal car with a batface on it. It's not a complete custom that Batman meticulously put together on his own by sending order for parts to a bunch of machining shop, but rather a solid base model modified for his need. If this is a Batman that's just starting out he hasn't amassed all the gadgets an older one would get.