The anti reflex coating was indeed developed by Zeiss (Smakula) shortly before WW II and in parralel by Kodak in the U.S. Both patents were classified as military secrets. Large U.S. warships has their own high vacuum "coating equipment" onboard for the re-coating of the optical gun direction equipment and the rangefinders as the coatings were very soft and not resistant against the rough environmental conditions. The Summitar (as well as the Xenon/Summarit) was in production during and after the war, the older lenses were uncoated, after the war since about 1948 they were single coated (blueish shine). Zeiss Jena began to coat their lenses e.g.for the Rolleiflex about 1948 too. Most lenses of that day had front lenses from rather soft glas types. In the following years also the coating layers became more resistant.