At first glance, with the Omega dial and the unusual movement one would think an early fake.
However, the pin set movement is of high quality and the case is 800 German silver. If it is an Omega case (doubtful) the serial number would put it at around 1918, much too late I think for that combination.
Maybe the dial of the original watch was damaged and replaced with the Omega dial and hands from a watchmakers salvage box.
While there are no marks on the movement to identify the maker, removal of the dial should show things like caliber, maker, serial number stamps and also show the setting works, which is like a fingerprint for watch movements.
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