I'd earlier taken the view that a later addition (British Proof) would adversely effect the value of my Krieghoff, although now I'm advised by a reputable forearms auctioneer that if I'd sought to sell any luger, other than Imperial it would have to be proofed before sale off the Island & into Europe.
Having seen some extensive British proofing with tons etc.. stamped on many visible part I'd be somewhat deterred, however, I was extremely relieved to have the most unobtrusive single proof strike under one grip & now have a pistol that would be far more marketable should I choose to sell (unlikely).
I have no plan to proof any of my 'left behind' lugers. This one was found in the UK & needed the proof before it could cross the water to me It would, however, seem more sympathetic proofing is available if so requested.
Brendan