Mmmm, a nympho-of-info-maniacs wealth of info pics -
So to sum up, an F - G model that was returned to be rebuilt/recycled as needed, was if refurbished to K equivelent standard became a G10/G14 depending on pre-existing kit and required the fitment upgrades.
K's were made as such 'brand new' (with more new than the amount of recycled/re-checked parts) in the factories.
And not that many were in reality were made, the production of them was only just being sorted out initiated (so it seems), and so, even less of those actually reached units due to the logistical nightmares within Germany