Many thanks for the info Artiebob. If these mods were to be available to you again it would be nice if one could confirm for instance if there was only one defensive gun.
This here is the only pic I have seen, or rather where I have noticed that we're talking about a modified machine.
My Ju88 classification skills are a bit sketchy but it appears to me we're talking Ju88D-1 because of two camera windows. Jumo 211 engines. Noticable is the engine exhaust staining and then it appears there's a lot of streaking from the front hatch, which also seems to have some sort of window arrangement in it.
The picture is apparently from a series covering the 1500th Feindflug or similar. I thought I had seen these pics in some publication but I haven't found it in any of my own books.