In my opinion, I would suspect that the book reference mentioned probably says how it is supposed to work from design perspectives, and with the pistol in proper tune for its ammo selection. It takes some work to get these old pistols to move during the shooting operation like perhaps they were originally intended; it has been for me anyway.
Wartime useage and layman abuse might get outside of that theoretical window. We all know the Luger will "work" with overly hot ammo, but the life of the pistol is shortened dramatically; just a matter of getting used to things I reckon; seems like all knowledge has a learning curve.
I would think that levering the toggle to make some indentations(some are right deep) that one sees over the years on some pistols might take a pretty stout boy. Again just another opinion.
The mark on the rear of the Luger gives me an indication of how the pistol was treated/maintained from a shooting point of view. I like some of the historical aspects, but finally moved to the shooting arena only; hence my interest in said marks. Pistol maintenance overall can make the Luger work as designed, I think that handloading or selection of ammo will take that aspect to the next level. I find that collectors and shooters have a bit of commonality, both care about the longevity of said pistols; but of course..........always a few ringers in both groups.....
Hopefully there will always be room in groups for the new guys and the old guys; hopefully remembering some of what Mom told us(me as well).