It's a beautiful looking Half Dollar. I'm going to call it AU-58 for the light rub on the highest points. It's not much wear, just enough for the discoloration. I can't see much luster in the images, but the details look nearly MS to me. I'd say it's in a SEGS holder?
These were the seller's pictures. A friend somewhat color-corrected the pictures to account for the orange light.
I'll go with AU55 and have no clue whether it straight graded or was QC'd. It all depends on who submitted it and/or what day of the week it was graded.