[caldrail]

No, I wouldn't expect that, although you could postulate that a particular version was experimentally adapted. So we have the V4 single seater prototype with underwing cannons for tank busting, intended for production as the B4.

The problem is that while the Heinkel 78 had good weight lifting capacity and gentle characteristics courtesy of the generous elliptical wings, it wasn't a small aeroplane, and wouldn't compete on equal terms with single seaters, so a rear gunner is actually desirable.