Where Do You Look First? | Morgan Dollar Grading Points

A lot of it depends the strike too. if it not a full strike you will
not see a lot of detail in the high points. The New Orleans mint is notorious for weak strikes. and it takes looking at quite a number of them to determine a weak strike. but when you do it is kind of like a light bulb moment. At least it was for me

I look at the cottonballs.

I'll quote from the ANA grading standards book:

"AU58 - Has some signs of wear: Liberty's hair above eye and ear, edges of cotton leaves and bolls, high upper fold of cap; high points of eagle's breast and tops of legs. Weakly struck spots are common and should not be confused with actual wear.
AU55- Slight trace of wear shows on hair above ear, eye, edges of cotton leaves, and high upper fold of cap. Luster is fading from cheek. Slight trace of wear shows on breast, tops of legs, and talons. Most of mint lustre is still present although marred by light bagmarks and surface abrasions.
AU50- Traces of wear show on hair above eye, ear, edges of cotton leaves, and high upper fold of cap. Partial detail is visible on tops of cotton bolls. Luster is gone from cheek. There are traces of wear on eagle's breast, tops of legs, wing tips, and talons. 3/4 of mint luster is still present. Surface abrasions and bagmarks are more noticeable than for AU55."

As for your coin, I'm not sure I see ANY signs of wear. Maybe under certain lighting and held at certain angles some "rub" will show, but I'll bet this doesn't drop any lower than AU 58.