Bf-109C-3
From Oct 1937, following successful tests with Bf109 V12 (W.Nr 1016, D-IVRU), surviving C-1s were modified to C’3 standard with wing nounted 20mm MG-FF.
A notable boost in firepower, but lacking the Emils improved performance. An either/or vs the E-1 that has only 4x Mg but a better engine.
Bf-109E-5
A reconnaissance version of the E-3 built in small numbers and planned to replace Hs126 in front line units. A downwards pointing camera was fitted behind the cockpit and armament was reduced to just 2 cowling Mgs.
Camera being installed in recon 109

Closed up you cant essily distinguish its special nature.

The camera proved troublesome and units modified them back to fighters with wing guns reinstalled. Without seeing the belly or reading the data plate it would appear to be a standard early E.
.
You get Emil performance with Bertha firepower. I would stick with just the production standard as the de-camered and upgunned aircraft would simply be to clise to ecisting tree variants.