Leica produced "coated" lenses during WW2 in some 1942/43 issues
Some lenses like this went to the Luftwaffe PK units (Propaganda Kompanie) or high ranking individuals in the party, some were engraved with military markings others not, most weren't.
These lenses are known as belag
lenses (German word for coated ~ and are marked in the Leitz delivery dockets as so) ~ they made every style of issued lens during WW2 with this mono coating, (Elmar's Hektor's Summitart's Xenon's)
they were trying to catch up with Zeiss whom by 1942/3 had far superior coatings, that were being used together with the *widely available to the military* (but, not to the civilians)
AGFA Color films.
I have a 1942 Elmar f3.5/35 that's a belag lens, use it often on my M8
Also for many of the pre 1942 lenses, after the war there was a booming anti-reflective coating business, that even some private photo shops in Germany offered, many of the American GI's who started to shoot with Kodachrome "over there" also sent the lenses back to the factory to get coated as well, that's why you sometimes see early 50mm Summar's, Elmar's and Xenon's with coatings, while they were sent back......