This is one of those hard ones for me:headbang: Its hard to tell if its wear or weak strike. However since I've seen other 1880 Morgans with better definition above the ear and several points in the hair , I'll say AU-58.
This one needs to be in-hand to be sure, but I don't see much evidence of uneven luster on the cheek, or the eagle's head feathers or wingtips, that'd convince me it wasn't MS. 63-ish, maybe better in-hand.
I would agree it is likely a weak strike common in O mintmarks. However, it looks like there has been the potential of having been dipped. I would say AU-58 unless I see it in hand.
I haven't got the coin in hand yet, but the person I bought it from assures me the luster is nice (and I trust them)