what E versions of Bf109 will be flyable?

[TheGrunch]

I've heard several times that the 109E never had an engine-mounted gun apart from as a problematic prototype that never went into production and that it's just a misconception that's been reprinted since an author in the '60s initially made the mistake of writing it. The best argument I heard against it being possible is that the oil tank would be in the way of the breech. This is just a vague recollection, though.