I didnt even pick up on the right facing CONSTANTINOPOLIS, but yes, they arent easy to come across either (though barbarous issues often contain such errors). The thing I was looking at was the chopped up Magnentius - after his revolt was crushed, it seems that a tribe in East Anglia made use of his old coinage by chopping it up into minims. They are tiny and so usually looked over. This one was a good example - unusually high grade and showed the face.