Nrowsing thru lots of Stug pictures myself as I have a Stug III Ausf B underway. Fairly common to find side skirts w zimmerit, or different camo patterns in fact cause they were easy to lose in the field and they would just liberate a missing skirt where they could find them.
The wire is for adding foliage, in fact on my B I’ve add extra tracks to the right sidde of the turret/casemate and thru those tracks I’ve crisscrossed wire as I’ve seen to. Mine won’t have skirts but I may string some more as it was a common field mod, just as the other guys have noted.
I built Tamiya’s Stug IV as my first kit back in the hobby a few years ago. I cut the side skirts apart, damaged them, painted a few differently and added some rough zimmerit w putty to one just to break up the monotony, I liked the result.
Thanks for all the replies. I have a MiniArt kit, no interior, waiting to be built, but it’s 2/1943 so no Zimmerit. Not that this rules out picking up a later Stug III kit that would need Zimmerit.