Well, I have to say that in-hand, and upon consideration, I think the coin is genuine.
Certainly the last thing it appears to be is a struck
fake.
My first impression was that it might be a
cast fake given some apparent softness of features, the surface texture (emphasized by traces of
patina in the tiny surface defects), and the shallow relief of the devices. However, on closer inspection the edge of the coin (not shown - but I'll take a photo if doubts remain) looks convincing with a slightly "layered" appearance that seems to be indicative of struck coins and is missing from a
cast procopius (ex.
romanseller) that I have, and there are some convicing micro cracks at the edge (some visible in above photos) that also appear to rule out a
cast. The low profile of the devices, given the lack of major wear, does appear a
bit odd, but there are places such as Sol's crown where there is greater height (esp.
good to see on a region of
fine detail).
The
patina of the coin seems very convincing (although the traces of
patina left in the tiny surface defects looks a
bit odd, especially on the original
auction picture), and under magnification it appears that the coin has generally been slightly over cleaned as can be seen on the
obverse legend in the 12-3 o'clock region.
The
style of the coin is absolutely correct for this mint/date/type - I'd be amazed if anyone could cut a
fake die so convincing.
So, all told, I'm all but certain that it's genuine. Any doubts remaining come from the dubious
provenance and yet-to-be totally exonerated company it keeps, rather than the coin itself.
I of course welcome all opinions, whether in agreement or otherwise.
Ben