Nice Pic! When one thinks of this rifle, use in the Russian Caucasus, Italy and Crete come to mind, but not typically North Afrika. One wonders which one (if any) of the pictured USGIs, got to bring this one home as a trophy...
I believe Generalmajor Ramcke's Parachute Brigade was surrounded in Tunisia and broke out with the loss of 450 men.
Maybe this 33/40 belonged to one of these men.
There was a gebirgsjager Regiment 756 in Tunisia and a 288 SV (Sonderverband) in Afrika as well. Both would or could have had one of these superb rifles.