I agree with your thinking. A small gold coin with a mintage of only 50,000 should normally all be produced with one pair of dies. Those are excellent pictures and I am sure that we are looking at a die crack and not a scratch. You should be able to easily confirm that with a magnifying glass. A die crack will be raised above the surrounding surface, while a scratch will leave a depression below the surrounding surface.
I have read that the U. S. mint in the mid 1870's was normally able to strike 100,000 Indianhead cents before replacing the dies. In some cases they were able to achieve up to 200,000 cents per die failure but that was only in rare cases.
Good luck on making your millions and I hope you can do it in well under 30 years.
Andy