My recommendation to you would be to buy nothing until you are able to get a feel for what a vintage watch should look like and how to spot signs of prior bad watchmaking or poor maintenance. I would say sit at the computer, look at pictures of the watch styles that interest you and ask questions for at least 3 months before making any purchases.
You seem to be falling prey to a common fault of new collectors -- over-eagerness. You want a good buy, you think you see something "special" because it is different in some way to other similar vintage watches you've found online. The seller tells you how "rare" or "unique" it is, which doesn't help.
These watches were mass produced in great quantities when they were new. In the 1940's and '50's, Omega sold hundreds of thousands of watches per year of many different types. There is no such thing as unique or rare with vintage Omega. What you are looking for is something that is original and not worn-out. That's what is really hard to find in today's market.
With respect to the above three watches, the first one looks original, but is very worn and suffered from water intrusion at one time. Unfortunately, there is no way to know how extensive is the damage without an inspection from a qualified watchmaker.
The other two are badly redialled and are parts watches to most collectors. The case on the last one is fake.
gatorcpa
