I am doing one of these, but I am using the CMK Einheits cab version, as that was closer to the version that mounted the 2cm Flak 38. Please bear in mind that there were official conversions of Steyr trucks to "Flakwagons", and there were field mods in a variety of forms. I am modeling one of the "official" conversions with a cut-down Einheits-type cab. If you look at the Afrika Korps website, there are a few shots of a standardized mounting for the 2cm Flak 38 that allowed this weapon to be fitted in the rear beds of any of the medium cargo trucks used in North Africa by the German forces. This same rig could possibly have been used on the Steyr 1500A or 2000A light trucks, snce the weight was well within the limits for the chassis. Note that all the "official" flak conversions seem to have used the Steyr 2000A chassis that had doubled rear wheels, but these could in fact be fitted to any Steyr light truck chassis.
For your project, you might want to see about using the standard mount mentioned above, and it would be quite authentic. Having finally found the photos, I do not believe the standard mount would fit into the back bed of a standard length Steyr 1500-2000A light truck. The official versions all used the later long-bed type. CMK does an attempt at this, but they didn't lengthen the chassis or the bed enough, though they could be modeling an interim short bed type. It's hard to tell because there were so many variants in everything the Germans built. The photos may be found on this page of the Afrikakorps website:
http://www.afrikakorps.org/panzerjagerabt.htm and scroll down about 3/4 of the page to the section on trucks mounting Flak guns. The mount is shown being manhandled into the back of a 3-ton truck with the gun already mounted. Those guys are stronger than they look.....
