These draw attention of EBay and typically are called divers but they were not part of the "Skin Diver" series. Yes the bezel is original and I would first say the model comes from the "Sport Series". Most likely dates to 1974 - 1977? The production numbers will be at the base of the dial. the last two are the year made. Preceded by movement number, model\series. If you can't see them than the movement has to be taken out. You may also find an ink stamp on the inside of the case back.
Is it running? If not I know a very reliable resource who would be very happy to get it back into shape for you
Here is his calling card -