I attended an estate sale where I had spotted an Omega, though passed on it due to heavy wear and high price.
However, I saw a very tidy Wyler Incaflex blue-dialed Dynawind with a clear, transparent caseback. I am guessing the watch is from the late 50s or early 60s. I am kicking myself for not taking a photo to post here. I made an offer of $50, so we'll see.
Anyway, I thought transparent casebacks were more modern adaptation, not something done in the 50s.