From what I'm seeing, 3Z+EH was modified in several respects, aside from it's unique camouflage, the bomb shackles were removed as was it's bombsight.
So it's entirely possible the crew could have installed a fixed MG for strafing. My guess would be a MG81, since it was belt-fed.
The time-period of this photo was circa 1941 when it was operating out of Sicily.