P.S. : Here are more microscope photos, of the edge of my fake Justinian I coin. It seems like, the remnants of a casting seam may be visible, in some of the photos.
Interesting! It seems like old fakes that one hoped would be sorted out by now keep showing up like bad pennies. Probably lots of old Black Sea Hoard fakes still around in the community too. A couple of months ago I bought an odd lot from an old Danish collection. I liked all the coins except the Justinian, and lo and behold: