Hi
A Lovely heirloom to find. I would also date it to the 40’s. I would expect it has a 30T2 movement inside. What’s the diameter of the watch without the crown? 32/33mm?
Get the watch serviced by a local watch repairer that deals with vintage watches, put a nice leather strap on it and enjoy. These movements are bullet proof and will run and run.
As stated the crown is wrong, but finding an original may be difficult.
Regards
Chris