What’s the story with this seamaster 300 dial

It’s a bullshit redial. That’s the story.

To answer the OP’s questions a little more fully, the dial shown (while clearly a redial or possible a fake) is made to look like the one on the original Seamaster 300 model, but closer to the second or third version and not the first.

The reason it looks like the dial in the newer 300 Master Co-axial is because that dial was patterned after the original.

Several reasons:

1. The original dial is probably 50-60 years old.
2. Swatch/Omega no longer sells replacement parts to independent watchmakers, unless they are certified by Omega.
3. Since independents do not have access to these parts, their only option is to get outside companies to do refinishing of dials. Unfortunately, almost all of these companies do not have the correct dies or equipment to come close to the original quality.
4. Omega may have replacement dials available, but only if the watch is sent to them for service. If not, then even Omega will send them out to be redone. The quality will be not perfect, but better than your example.

Hope this helps,
gatorcpa