Honestly, I'm going to say AU53. Here's why. The 1885-O is one of those dates with a very wide range of strikes...some are really good and some are really bad...and a lot are in between. I would say this coin has a nicer strike...but it's totally fully struck. That said, there is definitely wear on the hair above the ear and some on the cap. Some of the flatness seen there is the less than full strike...but the dull grey look of the coin in those areas is the loss of luster due to wear. So, with this coin showing wear it cannot grade above an AU. So, then what AU is it. To me, this coin is a low AU...I might even say technically an AU50. The reason is, it has a ton of hits. There are hits all along the neck and jaw of Liberty and a few in the fields. Despite this, the coin has lovely eye appear due to the toning so I think that will help it. The reverse has fewer hits than the obverse and that helps as well. So, for those reasons...I'm going to say AU53.
I always thought AU coins were graded based on the level of wear and the amount of original luster left, not contact marks. Also, under a 10x loupe, there half as many hits as there appears to be in the pictures. The toning is mottled in some areas, and my pictures create the illusion that they are hits.
That can play a part in it...but they are often graded the same way as an MS coin when it comes to contact marks. Yes, the amount of wear is an additional factor. This is partly why AU58 coins are so popular. Typically they are MS64 coins or better with just a touch of wear. But take an MS61 coin and put that same wear on it and it's probably AU53-55. Also, as far as what marks are there and what is the toning...that can be hard to judge in photos. Based on the photos, I stand by my grade. In hand I might think differently.
Play around with PCGS's interactive grading standards: http://www.pcgs.com/grades/ It seems like the AU-58 has the most bag marks of all of the AU grades. Also, notice how the luster gadually disappears as the numbers decline. My observations with PCGS's standards seem to be at odds with your standards.
You're basing that solely on a single photo at each grade point (not to mention of coins which have very different strike qualities). Look at a lot of coins and you will see. Yes, you are right...additional wear does downgrade an AU coin, but so do bag marks. This coin has wear...so it's definitely an AU. It also appears to have a lot of bag marks. From what I have seen, this will downgrade it further. Maybe I'm being a little hard on this coin...but it looks very baggy to me. Does that mean it would grade AU55...maybe. But, I don't see it any higher than this. Personally, I love AU58 coins because they often have wonderful eye appeal. They are certainly not baggy coins.
By your definition, these shouldn't exist: http://www.mistymountaincoins.com/shop/carson-city-mint/1892-cc-morgan-dollar-pcgsau58/ http://cgobr.com/product/1897-o-morgan-dollar-au-58-pcgs-graded/ http://www.lsrarecoins.com/1879-cc-1-morgan-dollar-pcgs-au58-cac-1741-1.html http://www.lsrarecoins.com/1878-7tf-1-7tf-reverse-of-1878-morgan-dollar-pcgs-au58.html I used the search term "PCGS AU-58 Morgan" in Google Images and grabbed the links to the first four images.
In my opinion, the 1878 and 1879-CC are very hard to judge in the photos because of the toning. My guess is that a lot of that chatter is the toning...not nicks in the surface of the coin. The 1897-O has a few more marks that I would have thought for that grade...and the photos really mute the luster. I'd imagine the coin looks much nicer in hand. The 1892-CC looks overgraded to me...but again, the photo could be making it look a lot worse than it is. It's hard to grade coins in photos. You don't have to agree with me. You are welcome to your own opinion on this coin as am I. I doubt I will change your mind and I doubt you will change mine. That's OK.
I agree with the good doctor on this one--there is definitely wear in the cap. People are just not seeing the wear in the cap and hair. As I've said before, this is not a MS coin, but is a mid level AU--I said AU 55, and am sticking with it. My experience with Morgans is pretty extensive, and I think I can spot a circulated Morgan. This one, while a lovely coin due to the toning, is circulated. There are contact marks as well that don't look like bag marks, but the dead giveaway is the cap/hair area.
Sold for $43 on eBay. I was hoping for more (about $50 after fees and shipping) because I thought the bidiots that pay $150 for a worn AT Morgan would bid it up. I also made the mistake of adding free shipping (which I overlooked because it is my default). That is LAST time I put a non-details coin up for auction. BIN forever onward for me!
For future reference this is a bad time to be selling coins especially auction style. The next few weeks should bump interest from Xmas eBay gift cards, but December, especially this close to Xmas, is a dead zone for selling. Picks back up in February after people build funds back up after Xmas spending