Just be aware, there’s an all fake Seamaster 300 for sale at Auctionshaus an der Ruhr in Germany. I’we notifyed them of this, and exchanged communications but they still insist it’s only a replacement dial on it and don’t pull it from their listing. Even when i’we informed them that the case, hands, caseback, dial and bezel are all fake. Movement is most likely from a Constellation. Here it is, if it helps anyone to avoid a costly mistake.
I have a very similar fake that I purchased on ebay years ago. Oddly enough these were being faked when the value of originals was only in the hundreds, not thousands, and I did wind up with a real movement out of it. Also I was not out a fortune. Unfortunately at that time ebay was more slanted towards sellers and I was stuck, even after opening up a case with ebay.