I personally find it great to "revive" orphaned movements in this way and make them usable again. It also opens minds of younger people to the beauty of pocket watch movements.
Imo still an Omega. Nobody would say that a recased Bunn Special pocket watch is no longer an Illinois 😉
This kind of mariages is offered quite frequently on eBay or Catawiki, so you might look there for concluded sales for finding out what to pay.
Cheers, Bernhard