I have come across a photo of a Pz.III Munitionsschlepper (ammunition carrier) with schurzen fitted. Clearly visible are a pair of rectangular cut-outs towards the top of the middle panels. Does anyone know what purpose these holes served, and whether they would be present on the panels on the other side of the vehicle?

This one?


They seem a little too regular to be a field mod. Perhaps it is so the crew could pass the rounds out to someone standing on the ground instead of someone needing to be on top - a two man job instead of 3 men? They could be inside the hull and lift the rounds up onto the hull top close to the edge. Then someone outside could reach in and grab it.

Interestingly, there does not appear to be schurtzen on the opposite side (at least no front panel)

Yes, that was the photo I had in mind. You have the same thoughts as me on this. I have come across other photos: some showing the vehicles without schurzen; others with schurzen, but without the cut-outs. As you rightly observe, this particular vehicle appears to have the panels on one side only.
The reason why I am interested in the vehicle is that I intend to build an Eastern Front diorama (in 1/72 scale), incorporating a Tiger I being re-armed from a Pz.III Munitionsschlepper (based on an image in the 'Panzer Colours 3' book).