I don't believe it was the most produced. While it was more elegant than the later bombers, it took a MUCH larger number of parts, manhours, rivets, etc, to build than the Ju88 and other models that replaced it.
It was inefficient to build, I mean. That's why I don't think it was the most produced. I think the Ju88 and sub-variants might hold that for "most bombers made by Germany"
EDIT: If you don't quite understand what I mean, look at the curves. It took a lot more parts to make up a smooth curve, a lot more time to fashion/shape them, and a lot more folks to make them and get them onto the plane properly, whereas the Ju88 has a straight-walled (almost square) cross section along the tail and could be created with much less bending, folding, and less parts overall.