I will fess up - I made the request to Brent after being dissatisfied with my own attempt at a conversion:

Does that MG actually clear the armor in front of the driver to actually shoot out the front, or is it only usable for left and right firing arcs?
As far as I can tell, the two machine guns are only set up to fire to left and right arcs. The armour plating on the sides can be raised or lowered as needed. They originally had Colt MG in 1915, but those were eventually replaced with Vickers.
Like other early armoured cars, the Autocar was a slap-dash affair, as armour plate was bolted on to an Autocar truck chassis. By 1918, the car was obsolete, but still saw some action in defense against the Michael offensives and in the attack during the 100 Days.
More info on the Autocar can be found on Landships:
http://www.landships.freeservers.com/new_pages/autocar_ac_info.htm