Thanks John. I think the box was designed for this pistol, since the green cutout fits better:
https://forum.vintageairgunsgallery....l-6/#post-2287
but I've no reason to think this Kempton one wasn't sold in that box. Very interesting that it has no markings, neither the Diana inscription on the cylinder or a serial number. The extra diameter 'muzzle weight' under the front sight has also been seen on other very early woodstock mod 6s. It was phased out on the later ones.