Hard to say if anything was replaced without more photos.

You'll probably have to have one made. I'm not aware of these being sold as loose parts.

Caliber 4xx Jaeger-LeCoultre fromn the 1940s are rather nice and still not all that expensive.

Yes it is real. U.S. market, 1950s. The hand made etchings are probably marks watchmakers put in during servicing for their own reference.
I don't have any other information unless I see the movement and have its serial number.

The watch dates to approximately 1945. 18k gold, perhaps movement caliber 480.

Post them individually if you must, thanks.

What does the back look like?

It will depend mostly on the gold content of the watch.

There is a table in my book, but I do not make it public.

Your watch dates to approximately 1965/66

The movement number should be stamped near the balance wheel. It could be a 469. If your serial is around 1.4M it would be around 1960-61.