There's lots of youtube vids about the "coin" thing even from reputable repair shops.

I tried it on something I knew had damage and you had to be darn near perfectly on top of the known and visible crack to hear the change.

I tried it on another bike with a much more involved repair job, and it worked. Get near the dime sized HOLE and the pitch changed.

If there aren't any paint imperfections the coin trick might not even work.

I'd ride it as-is and set a reminder to inspect it each week for a few months, visual check.

That's all.