As pointed out above, you and @walkman2727 are asking about the same watch.
And neither of them have provided any research done by themselves etc.
Lazy Bastards , like Australians lovingly used to call them ...
Yes I did do my research and i think it is legit but I am far from an expert and it looks like there are many variations of fakes I am not aware about. Seamaster 300s are a minefield as you all know. I can write a dissertation about why I believe it is original but what would be the point, there are countless little details that I wouldn't know about whereas an "expert" would ping it for a fake or the real deal in 10 seconds...