Hi Rob,
According to my research for this vehicle and review, the L1500A was issued as a prime mover for light guns, such as the 2cm FlaK 30/38, 3.7cm FlaK 38/43 and possibly even the 3.7cm PaK 35/36. Generally though it was used as a personnel carrier and a heavy staff/command car. I haven't seen any photos of L1500A's, by any of the three manufacturers (Steyr, Horch or Mercedes-Benz), towing a 5cm PaK 38. I believe the 5cm PaK's generally used half-tracked prime movers such as the Sd.Kfz. 10, or even the RSO. But I suppose, in a pinch, the L1500A could have been used. MiniArt has also releasded the cargo version of the L1500A and you might consider this one as well. It's on my wish list.
See here:
http://www.miniart-models.com/index.htm?/Catalogue.htmI hope this answers you questions.
Cory