I took a real good, slow look at it and before I saw your guess/assessment I came up with the same grade…AU50. I almost said AU53, but the patches of wear on the reverse were rather prominent. That being said, that is a downright nice Trade Dollar even at a AU50…Spark
I’d have to say it’s a XF-40, maybe 45. Too much wear for an AU grade. It is very nice and no chop marks.